Energy is sustained in the form of mechanical energy.
Mechanical energy is converted into kinetic or potential energy of the system.
Internal force is a conservative force.
The external force is not a conservative force.
The internal forces acting within the system are in opposite directions to each other, the forces cancel out and hence there is no net work done on the system.
The external forces act in the direction of the force imposed and the work is done.
Some examples of internal forces are gravitational force, magnetic force, electric force, spring force, etc.
The internal force reacting within the object doesn’t cause the acceleration of the object at rest but there are internal actions that result in a change of energy of the system.
Internal forces are the forces acting within the system, which may be due to dipole moment, the motion of the molecules or charged particles, density, etc. Examples of internal forces are gravitational force, electric and magnetic forces, spring force, etc.
Due to the internal actions, the potential or kinetic energy of the object changes to the mechanical energy of the object which is conserved by the system. Since the acceleration of the object due to internal forces is zero, this implies that there is no momentum of the object and hence the work done by the system is always zero and the mechanical energy is also conserved. Hence, the internal force is a conservative force.
How internal forces act on the system?
The internal forces within the system act in a direction opposite to one another thus canceling out and resulting in zero output.
The internal forces mainly appear to resist the changes caused by external forces or in response to the external agents that may be due to electric, magnetic field interaction, or temperature change.
On introducing the material having magnetic characteristics in a magnetic field, the dipoles get arranged in the direction of the field. The magnetic flux lines traversing internally cause the magnetic spin dipoles to get aligned according to the field.
An object always exerts a force due to the gravity of the Earth that relies upon the mass of the object.
What is the External Force?
The external forces are the forces acting on the system due to external agency.
The external forces cause the object to displace or resist the motion of the accelerating object. Some external forces are applied force, air resistance, tensional force, normal force, frictional force, etc.
The object at rest has zero kinetic energy, when the external force is applied on the object, the potential energy is converted into the kinetic energy that is utilized in accelerating the object until it experiences a force to resist its motion due to which the kinetic energy is again converted into potential energy.
According to Newton’s First Law of Motion, “the object will be in a state of rest on in a continuous motion at constant speed unless and until some external force is exerted on the body.”
The external force is required to either accelerate the body or to resist the motion of the object. This could be applied force, normal force due to the weight of the system, a force due to air resistance, or frictional force exerted on the body that resists the motion of the body dragging it backward.
The equal and opposite force reacting on the object in a direction opposite to the normal force due to weight and geometry, and across the length of the object is a tensional force. This force is created across the length of the body when a load is applied to the material.
Examples
Let us discuss some examples to understand the internal and external forces exerted on the objects.
Car Climbing Up the Hill
Consider a car climbing on a hill. T is a tensional force, N is a normal force, the force due to friction and air drag acting backward and force due to gravity is acting towards the ground from the center of gravity.
Car climbing on the hill
For a car to climb up the steeper hill, more acceleration has to be given to the car. The steeper the slope of the road more you need to provide the acceleration because the internal force due to gravity is pointing backward and also the frictional force and air resistance drag the car down the slope.
The more the force acting backward, the equal force will be required for a car to climb the hill; this will create a tensional force reacting forward that keeps the car accelerating forward.
Man Pushing a Load
Consider a man pushing a load of mass ‘m’, the force due to gravity on the object is ‘mg’. The normal force is against the weight of the load.
Man pushing a load
When a force is applied to displace the object,a frictional force is applied on the surface of the object simultaneously on rubbing to the ground. The greater the mass of the object more will be the frictional force into action. The friction of the surface depends upon the pattern of the surface, less friction will be produced if the surface is smooth, more the roughness of the surface more will be the frictional force on the object accelerating on the surface.
Contraction and Expansion of Rocks
Contraction and extension of the rock forming the cleavages on the surface of the rocks are due to the thermal agitation and varying weather conditions causing the cleavages and erosion of the rocks.
Fractures on a rock due to contraction and extension, Image Credit: Pixabay
During the cold weather, the molecular distance constituting the rocks contracts whereas in the hot summers the molecular distance expands which results in the formation of cleavages on the rocks. This is only due to the internal activities going within the composition of the rock due to the absorption and emissivity of sunrays.
Weight Attached on a Pulley
Consider a pulley with masses attached on both the ends of the rope, m2>m1. Since the mass m2 is greater than m1, m2 will accelerate down. Due to the weight imposed on both ends of the rope, the tensional force will be created across the length of the rope.
Mass attached on the pulley
The force acting on the mass m1 is the sum of the external force due to tension in the rope due to the attached mass and internal force due to gravity acting downward and given by the relation,
F1=T-m1g
m1a1=T-m1g
Since the acceleration of the mass m1 is upward in the direction opposite to the force due to gravity, hence it is negative.
The force acting on the mass m2 is a gravitational force in the direction of the acceleration of the mass and opposite to the tensional force acting across the length of the rope from the pulley.
F2=m2g-T
m2a2=m2g-T
On what factors does the internal and external forces depend?
The internal and the external forces in actuality depend upon the intrinsic as well as the extrinsic factors and amount of force imposed on the object.
The internal forces within the system depend upon the dipole moments, internal heat of the system, emissivity, temperature of the system and the surrounding, composition, weight, density, the separation between the molecules constituting the system, motion of the particles in the system, geometry of the system, molecular constituency, covalent bonds between the atoms, number of free particles, etc.
The external forces depend upon the extrinsic properties influenced on the system like how much is a force applied, the normal force due to weight and configuration, the frictional force due to the surface in contact with the object, the air drag, tensional force, etc.
What forces act on the object floating on the surface of the water?
The force that causes the object to float on the water is a buoyant force.
The buoyant force is acting upwards on the object due to the volume of water which is the external force, whereas the internal force of the object that is the force due to gravity is always acting downward.
What are the various forces employed on the bullet fired from the rifle?
On firing the bullet, the accelerating force is applied on a bullet equal and opposite to the recoiling force on the gun.
When a bullet is in the air traversing the air column, the air resistance drags the motion of the bullet due to which the frictional force comes into the act as the bullet passes brushing the air while the gravitational force is acting downward.
What forces are associated with the athlete while running?
The athletic is able to run because of the gravitational force acting downward and the frictional force that prevents the athletic from falling.
Most importantly the muscular force is required by the athlete to accelerate his/her body which is an internal force involved by the athlete.
Why the center of gravity of an object doesn’t change on the application of internal forces?
On acceleration of the object the center of mass moves along with it.
The object doesn’t accelerate due to the cause of internal forces hence the center of gravity remains constant.
Why spring force is an internal force?
The spring force helps the spring to regain its original form. Every spring has different spring constants.
When a load is imposed on the spring it is stretched gaining the potential energy that converts into kinetic energy while the spring tries to come back to its original shape and size resulting inharmonic oscillations.
The vector sum of all forces that act on a body at the same time is known as the net force.
Since net force is the sum of all the forces acting on a body, and as fore is a vector quantity, it naturally makes net force a vector quantity, having magnitude as well as direction.
Net force can also be referred to as the resultant force.
In this article, we shall try to find is net force a vector? Though we’ve already established it above, we shall try to find out why and how.
What is Net Force?
Before answering the question, why is net force a vector? Let us first understand what the net force is?
The net force is the vector sum of all the forces that act on a body at a given time.
The net force appears when multiple forces act on a body. This net force generally causes acceleration to the body. Now, accelerating does not necessarily mean increasing speed; it generally means the change in speed. So, the decrease in speed is also known as acceleration.
So, if a body starts to move with the help of the net force, a time will come when the body will slow down; it is also known as acceleration, and the word generally used for that is deceleration. So, the body will decelerate with the help of net force itself. The magnitudes of net force will change, which causes the deceleration.
When the net force is zero, it means that the body is in motion, but it is not accelerating (it has constant speed), or the body is at rest.
When the net force has a non- zero value, it means that the body is accelerating. Sometimes, this value may have a negative sign, it expresses the direction of the body.
Vector Addition
In vector addition, the size of the arrow represents the magnitude of the vector quantity. The length of the arrow is equal to the magnitude of the quantity.
The vectors are added when the arrow- heads point in the same direction, even if the direction is otherwise than shown in the picture above.
They follow simple mathematical rules. The arrows are just to represent the direction. As evident from the picture above, if one arrow is in the opposite direction from the other arrow, its magnitude will have a negative component.
From the above picture, it is evident that +4 and -4 results in 0 net force. Therefore, when the net force is zero, all the forces are balanced. The rest of the examples are simply the case of unbalanced force. So when the forces are unbalanced, it causes acceleration in the body. This acceleration progresses in the direction of the force with a greater magnitude than the other quantity.
The formula for calculating the net force is given as:
FNET = F1 + F2 + F3 + ………. + FN
Where,
FNET = Net Force
F1, F2, F3, … FN= Forces acting on a body
If the forces acting on a body have different S. I. Units, then the units are converted into Newton (the S. I. Unit of force), and then the forces are added so that it is easier to add and saves a lot of mess.
If a net force affects an object, that object will accelerate. Conversely, if the object accelerates, it must be influenced by the net force. The magnitude of the net force acting on an object is equal to the object’s mass.
Why is net force a vector?
Anything that has magnitude and direction is known to be a vector.
Theoretically, a quantity must follow certain mathematical rules to prove that it is a vector. These rules are recognized as the laws of vector addition.
Let us take an example for understanding is net force a vector. Say a box is lying on a table. Various forces will work on this box. Initially, when the box is immobile, a gravitational force will pull the box in the downward direction, and an equivalent normal force will oppose this force and pull the box in the opposite direction, i.e., the upward direction. Therefore, these forces stabilize each other and align in an equilibrium position, and we say that the box is NOT moving or it is stationary.
In situations like these, where an object is placed on a table, the normal force is also referred to as the supporting force or the contact force.
No force can ideally balance each other; each and every force is unbalanced. There will always be a minor difference between the magnitudes of the two forces, but this difference is so small that it can be neglected. And hence we can say that the forces balance each other.
Newton’s first law of motion states that ‘a body will remain in its state of motion or rest until an external force is applied to it.’ So, when a body is at rest, it does not mean that no forces are acting on it. It simply means that the forces acting on it have the same magnitude but in the opposite direction, and hence, these forces balance each other, and the net force is zero. Thus, it seems as if no forces are acting on it.
If we want to slide the box in one direction, either left or right, we apply force (push) in that direction. Say we want to move the box on the right side; we push it from the left side to the right side. This means that we applied an external unbalanced force on the box to change its state of rest.
Picture showing all the forces acting on a box
Now the question arises, why is this external force unbalanced?
This external force is unbalanced as there will be a force in the opposite direction, known as the frictional force, but it will not be of the same magnitude as that of the external force, and hence, the external force will be unbalanced. In this case, the magnitude of the external force will be considerably more significant than the frictional force.
On the side of frictional force, there will also be air resistance acting in the opposite direction to that of the external force, but it won’t be essential. Even after combining the magnitudes of the air resistance and frictional force, it won’t be equal to the applied external force. So, the box will not be in an equilibrium position anymore, and thus, with the help of external force, it will move in the right direction.
Thus, as the gravitational force and the normal force balance each other out, the box will not move vertically. But, as the external force and the frictional force do not balance each other, and the magnitude of the external force being greater than the frictional force, the box will move in the horizontal direction. More specifically, in the right direction.
The direction is an essential component to be considered for a quantity to be a vector. As force is a vector quantity, and as the net force is the sum of all forces, one can anticipate net force to be a vector quantity.
Force is a vector quantity, and its S. I. Unit is Newton.
To be a vector quantity, one should have direction as well as magnitude. As force has both direction and magnitude, it is a vector quantity.
Is force a vector quantity? Absolutely, it is a vector quantity. It is evident that each and every quantity has magnitude. But, in this case, it would be very confusing if one does not know the direction, it would be impossible to solve the puzzle. And hence, the force has both magnitude as well as direction. Thus, it is a vector quantity.
What is Force?
Force is an external factor responsible for changing the state of the body.
It would either push the body to get it into motion, or stop it from being in motion; it can work both ways. The famous Greek philosopher Aristotle said that force causes “unnatural motion.”
As force is a vector quantity, it is denoted with an arrow above it as:
The formula for deriving force is given as: F = m.a
Where,
F = Force
m = Mass of the object
a = Acceleration
Force’s S. I. Unit is Newton (N) or kg. m / s2.
Dimensions of force are given as: LMT-2
Further, three concepts are related to force. First is Thrust, in which the object’s velocity is increased. Drag, in which the object’s velocity is decreased. And Torque, in which the object’s rotational speed is changed. Pressure can be referred to yet another type of force, and it is the distribution of small forces applied over a body.
There is contact force, which needs physical contact between two objects to occur. Contact forces include some non- fundamental forces, examples of which are given below. Then there are non- contact forces that do not need physical contact between the objects. Non- contact forces include the fundamental forces given below.
There are four elemental types of forces in nature.
Gravitational Force – it is a universal force that acts between masses and it is always attractive.
Electromagnetic Force – it acts between charged particles and it is ten times more powerful than the gravitational force. It can be attractive or repulsive. Magnetic force is a type of electromagnetic force.
Weak Nuclear Force –It appears only in specific nuclear processes like the nucleus’s beta- decay (β- decay). It is more powerful than gravitational force but feeble than the electromagnetic and strong nuclear force.
Strong Nuclear Force – it is more potent than all fundamental forces of nature. It holds together protons and neutrons in the nucleus. Electrons do not experience this force.
When fundamental forces interact with each other, as a consequence, non- fundamental forces arise. Some of the non- fundamental forces are:
Normal Force – it acts perpendicularly to the surface to which an object contacts.
Tension – it acts when an object is being pulled by ropes, strings or cables, etc.
Elastic Force – it acts when a body returns to its initial shape and size after being stretched. The body is said to be uninfluenced by the force.
Stress – it is the force acting per unit area on a body.
Centripetal force – it is also called fictitious or pseudo force. The object is obliged to follow a curved path. It tends to pull the object at the centre.
Centrifugal force – it too is fictitious or pseudo force. It is the opposite of centripetal force and tends to pull the object away from the centre.
An object should have both magnitude as well as direction to be a vector quantity.
As we learned above, to be a vector quantity, an object should have both magnitude as well as direction, but that is not enough. For being a vector quantity and to prove it mathematically, an object ought to follow the laws of vector addition or subtraction.
As an example, let’s consider a box lying on top of a table, various forces are acting on it. A gravitational force will pull it down and an equal and opposite normal force will pull it up. Now, these forces balance each other, and as a result, the net force will be zero, and we say that the box is not moving.
Now, if we want to move the box, we need to apply some force to it. But on which side? If we say we applied a force of 3 Newton on the box, how will we know where the box moves? Thus, it is necessary to mention the direction. It will make sense if we say that we need to apply 3 Newton force on the right side, making it easier to understand that the box moves in the right direction.
Thus, if we want to move the box to the left side, we push (apply force) on the left side, and if we want to move the box to the right side, we apply force on the right side.
Representation of a Vector
There are many different methods by which vectors can be added or subtracted, which we will study further in this article.
Laws of vector addition include
Addition or subtraction of components of a vector
Triangular law of vector addition
Parallelogram law of vector addition
Polygon law of vector addition
First, let us briefly understand the laws of vector addition.
Triangular law of vector addition is applied when two vectors are arranged head to tail format.
Parallelogram law of vector addition is applied when two vectors are arranged head to head or in the tail to tail format.
Addition and subtraction are performed in simple mathematics.
Vectors cannot be added or subtracted to scalars and vice versa.
Vectors of the exact nature can be added or subtracted. For example, force should be added or subtracted with only force and not with velocity or any other vector.
As mentioned above, it should be proven mathematically to show that the force is a vector.
Addition or subtraction of components of a vector
For the addition or subtraction of a vector, the components of the vector should be added or subtracted.
For example, let below are two vectors.
Then the sum of two vectors will be:
The difference between the two vectors will be:
Triangular law of vector addition
In this method, the head of one vector is joined to the tail of another vector, and as a resultant, a diagonal is formed, which is the resultant vector. It follows the head- to- tail format.
Triangular law of vector addition
For example,
Hence,
When one wants to find the angle between vector
, it can be found using the formula:
Parallelogram law of vector addition
In this method, the tail or head of one vector is joined to the tail or head of another vector, respectively, and a diagonal is formed as a resultant. It follows head- to- head or tail- to- tail format.
Parallelogram law of vector addition
Hence, the formula for finding the resultant will remain the same as the triangular law of vector addition. i.e.,
Polygon law of vector addition
In this method, every side of a polygon will represent a vector. This polygon will be divided into triangles, and with the help of the triangle law of vector addition, it will be easy to calculate all the vectors.
This law is valid for any number of vectors and is always represented in a cyclic order.
Polygon law of vector addition
Why is Electric Line of Force a Vector Quantity?
The fictitious lines that illustrate the direction of an electric field are known as the electric lines of force.
The electric line of force is a force, thus, it is a vector quantity. Factually, force is a vector so it clearly makes the electric line of force a vector quantity. Hence, it has both magnitude and direction.
The electric line of force is popularly known as the Electric Field, and it is given as force per unit charge. The S. I. Unit for electric field is Newton per Coulomb (N/C), or sometimes also given as Volts per meter (V/m).
The formula for electric field is given as:
E=F/q
Where,
E = Electric Field
F = Force
q = Charge
Electric Lines of Force
As evident from the picture above, electric field lines are represented by vector arrows. As shown above, if the charge is positive, the lines come out of the charge and if the charge is negative, the lines go into the charge.
If only positive charge is present in space, then it is said that the electric lines of force come out of a positive charge and extend to infinity. Similarly, if only negative charge is present in space, then it is said that the electric lines of force come from infinity to the negative charge.
The lines are shorter when near a charge and longer when away from it. Electric lines of force never intersect each other yet being extremely dense. When the electric lines of force meet the surface of any object, the electric lines of force become perpendicular to the surface. These lines are not visible but experimentally proven.
Hence, with the help of direction, we can signify that positive charges attract negative charges but repel other positive charges. Similarly, negative charges get attracted towards positive charges but repel other negative charges.
Thus, if one wants to describe the electric lines of force, it cannot be done without the help of direction. One can establish if the charge is positive or negative only with the help of direction. Once the unknown charge of the charge is established, one can find the electric field, its strength, electric flux, etc. thus, we can say that the electric lines of force are a vector quantity.
In this article, let us discuss whether gravity is a conservative force or non-conservative, and secondly, is gravitational force a central force or non-central.
Gravitational force is said to be a conservative force because the work done on the object to travel from one position to another is independent of the time taken and the magnitude of the force is constant.
What is Gravitational Force
The gravitational force is one of the fundamental forces in nature and is the weakest force of attraction.
The two objects having mass exert a force of attraction on each other, and this force is centralized at a focus between the line joining the two objects. As the distance between the two increases, this gravitational pull among the both becomes weaker and weaker by the square of the distance separating them both.
The law of Gravitation states that “Every object attracts every other object in the universe by the force which is directly proportional to the product of the two objects and inversely proportional to the square of the distance between the two” and is denoted by the equation:
F=G*(m1m2)/r2
G=6.67*10-11
Where
m1 is mass of object 1
is mass of object 1
m2 is mass of object 2
is mass of object 2
‘r’ is a distance between the two objects
At r=∞, the gravitational force will be equal to zero.
Why Gravitational Force is Central Force
When the two bodies are bounded by the gravitational force of attraction, the force imposed is equal in magnitude and acts in opposite directions towards each other separated by a distance.
Consider a satellite revolving around the Earth. The mass of the satellite compared to the Earth is very negligible and hence the Earth will accelerate at a very minute rate than that of the satellite. The gravitational attraction between both will tend the satellite having less mass than the Earth to revolve around the Earth in a circular orbit. This follows Kepler’s 2nd Law, according to which “the line joining the satellite to the planet Earth will sweep equal areas in equal interval of time”.
For a body to keep in a continuous motion the force has to always act towards the center and the velocity of the object radially pointing outward. The magnitude of the force at the focus depends upon the length of the separation between the centers of gravities of both systems. The gravitational pull between the two keeps the satellite revolving around the Earth in a circular orbit, hence gravitational force is a central force.
Satellite revolving around planet Earth; Image Credit: Quora
The satellite around the planet will move in uniform circular motion under the action of a centripetal force given by
Fc=mv2/r
Equating this with equation of gravitational force
mv2/r =G*(Mm)/r2
‘v’ is the speed of orbiting satellite around the Earth.
The cycle maintains its momentum while riding is actually because of the central force absorbed by the spinning wheels that help to keep the momentum of the cycle constant and hence the rider is able to keep the cycle in a vertical position. If the momentum applied to the cycle is equal to zero then the cycle will fall on the ground. The direction of the angular momentum lies along the axis of rotation. The greater the speed of the wheels more will be the momentum of the cycle. We can ride a bicycle as the momentum is conserved because of the circular motion of the wheels.
In the same manner, the momentum of the satellite is conserved due to the central force acting due to the gravitational force between the Earth and the satellite.
Why Gravity is Conservative Force
Gravity is a force of attraction experienced by objects towards the center of the Earth. Every object having mass possesses a center of gravity and is bonded to one another by the gravitational pull of attraction. The gravitational force is a long-range force between the two bodies having mass and does not depend on any field and therefore is a non-contact force.
The weight of any object on the Earth will be the mass times the acceleration due to gravity. The potential energy of the object at a certain height above the surface of the Earth is P.E. = mgh. Work done in bringing the object from height ‘h’ to the surface of the earth is the same as the potential energy associated with that object at a particular height ‘h’.
The body at rest has some potential energy associated with it, if there is a slight change in potential energy then it is obvious that there is some work done by the system. The work done in a close path is always zero as the force experienced on the bodies is independent of a path taken and hence the gravitational force is conserved.
Work done to displace the object from one place to another is
Work done to displace the satellite from point 1 to point 2 is
Since work is associated with the potential energy, Potential Energy U= -G*(m1m2)/r2
This implies that the momentum of the object in orbit is conserved and no work is done in this process hence the total energy is conserved. Therefore a gravitational force is conservative.
Unit of Gravitational force
The unit of gravitational force is Newton, named after the scientist Isaac Newton for his discovery.
The value of the universal gravitational constant G is 6.67*10-11 N.m2/kg2. In the CGS unit we have
Therefore, the unit of the gravitational force is Newton.
The range of the gravitational force is infinite. The gravitational force is strongest between the objects having high masses and are closest to each other; the same becomes weaker if the distance between the objects is much larger and at an infinite distance, no gravitational force is observed.
What is a central force?
Spring force, electrostatic force, gravitational force, centripetal forces are some examples of the central forces.
Force acting on the object is directed along the line joining the object and the origin is called central force.
Will you observe a change in your weight if you move from Goa to Greenland?
Yes. Greenland is located near the North Pole of the Earth.
As the acceleration due to gravity is greater at the poles there will be a slight increase in the weight than your weight measured in Goa.
In this article, we are going to discuss some of the central force examples in brief, and understand the detailed facts.
The following is a list of the central force examples:-
Uniform circular motion:
An object following a circular path without changing its speed, then the object is said to be moving in a uniform circular motion. The acceleration of the object is due to the changing velocity which is seen mainly because the direction of the velocity component keeps on changing as the force is tangent to the circular path of the object. Though the velocity of the objects varies with the tangential force, the speed of the objects remains the same.
If the velocity of the object slightly falls down then the object will accelerate inward. This is because the force is directed towards the center which is perpendicular to the motion of the object.
The acceleration due to circular motion is equal to
You must have come across a fairground ride in amusement parks. It consists of chairs suspended by strings attached to a circular large disc at the center. As this disc rotates, the strings attached to it will rotate with a person sitting on a chair in a circular motion.
The fairground ride does not have a uniform circular motion as the speed is not constant and the direction of velocity keeps on changing. Whereas the force is directed towards the center and the velocity of the person sitting on the chair is perpendicular to the direction of the force. This is a centripetal force and due to the centripetal force, a tension is generated in a wire attached to the chair which balances both the centripetal force as well as the gravity.
When the car is taking a turn in a circular path, a central force acts inward in order to neutralize the centrifugal force acting outward. The frictional force between tyres and a metallic road provides a centripetal force necessary for a car to take a turn.
A cyclotron works on the principle of electromagnetism which has both electric and magnetic fields perpendicular to each other and charged particles accelerates in this field to attain high energies. It consists of two discs that have a semi-circular D-like shape called Dees.
The frequencies of the particles revolving inside the cyclotron do not depend upon the energies associated with the particles. When the particle is released inside the cyclotron, the electromagnetic field allows the particle to go in a circular path inside both the Dees. The particle is accelerated due to the electric field. The acceleration of the particle increases the energy of the particle. With increasing energies, the radius of the circular path traveled by the particle also increases. The magnetic field guides the particles to exhibit a circular motion.
Gravitron:
Gravitron ride is another exciting thing to do at the amusement park. A person is made to stand against the cylindrical wall and gradually the speed of the gravitron is increased. As the rotational speed of the gravitron reaches very high, the floor beneath the person standing on is removed but surprisingly the rider remains attached to the wall of the gravitron.
The rider standing insider the gravitron experiences the centrifugal force which is equal to three times the force experience due to gravity thus allowing the riders to remain attached to the wall of the gravitron other than falling down on removal of the floor underneath.
Ceiling fans:
The rotation of the propellers depends upon the rotor to which they are fixed. The rotor works on the principle of electromagnetism. As the current flow in the coil, the magnetic field is induced in the coil that produces torque around the axis of the rotor. The magnets in the rotor of a fan are repelled by the stator that helps to increase the speed of the rotor. The rotor and stator repel themselves away from each other for every cycle. The circular motion of the rotor makes the blades of the fan move in a uniform circular motion. Hence, is also one among the central force examples.
The windmills convert wind energy to electric energy; and are also used for milling grains, extracting oil from seeds, pumping water from underground, etc.
As the blades move when there is enough wind speed to move the blades, the shaft starts to spin producing mechanical energy out of wind energy. The motor helps to increase the number of rotations per second, which is then connected to a generator to convert the mechanical energy obtained to electric energy. The motion of blades of the windmills is an example of a central force. The velocity of the blade is in a circular path and the central force acting towards the center makes the motor spin at high speed.
Motion of electrons around the nucleus:
Motion of electrons around the nucleus; Image Credit: bccampus
The bulky mass comprised by the atom is concentrated at the center called the nucleus of the atom and the lighter masses are found revolving around the nucleus of the atom.
Mass of the proton mp = 1.67*10-27
Mass of the neutron mn = 1.76*10-27
Mass of the electron me = 9.1*10-31
The mass of the electron is very small as compared to proton and neutron. The electron is a negatively charged particle and protons add positive charge inside the nucleus since the neutrons have no charge, the difference in the charges attracts towards each other, but the wavelength of the electrons is much larger than the radius of the proton and hence electrons and protons do not collide with each other.
The revolving electron is associated with the centrifugal force that balances the force of attraction between the two oppositely charged particles and escapes the electron falling into the nucleus.
Artificial satellites around the Earth:
Satellite revolving around the Earth; Image Credit: Quora
The satellite around the Earth is revolving in a uniform circular motion due to the gravitational pull of the earth. As the mass of the Earth is far greater than that of the satellite, the satellite experiences the force towards the center of the Earth and the velocity of the satellite remains perpendicular to the direction of the force that tends to keep the satellite revolving in a circular orbit around the Earth.
The satellite will move in a uniform circular motion around the Earth under the action of a centripetal force given by F=mv2/r which balance the gravitational force and hence,
mv2/r =G*(Mm)/r2
‘v’ is a speed of artificial satellites orbiting around the planet Earth.
Ferris wheel:
Ferris wheels are giant wheel in the amusement parks that spins upward with the help of gears and motors, while the gravity of the Earth pulls back the wheel down to the normal position and this is repeated. The wheel is rotated about a central axis. The force due to centripetal acceleration that acts towards the center of the wheel is
Acceleration of the Ferris wheel; Image Credit: RealWorldPhysics
When a wheel is moving from downward to the upward position, it needs enough force to move upward opposing the gravitational pull acting downward. The acceleration of a wheel is pointing upward. The force experienced on the body is the sum of the centripetal acceleration and also the gravitational force which is given as
F=m(g+a)
Where
As the height from the ground rises, the potential energy of the body increases and the passenger feels heavier by weight.
On reaching the top of the wheel, the centripetal acceleration is now pointing downward. The force experienced on the person now will be minimal because the gravitational pull itself accelerates the wheel downward, hence the total force experienced on the body is.
At this point, the potential energy is converted into kinetic energy and the body freely accelerated downward without experiencing any force. This can also be called a free fall of the body. Hence, the passenger feels lighter from this point till reaching the bottom of the wheel where the kinetic energy of the body becomes almost zero and restarts building the potential energy.
Mixer Grinder:
A shaft rotates due to the motor coupler on the main unit and at the base of a grinding jar. With a rotating shaft, the blade attached to a shaft also rotates and helps in grinding the mixture. The rotation of the blade is associated with the central force axis at the shaft. The spinning of the blades sets food particles in a circular motion; this creates a vacuum at the center and moves the particles towards the sides of the jar.
What is a Central Force
Force acting on the particle or an object directing towards a fix point at the center along the line joining the object in space and the magnitude of the force depends upon the distance between the object and the focus is called a central force.
It comes into action only along the line joining the two objects interacting towards each other and is exerted at the center of the two bodies.
The angular momentum possessed by the object in a circular path is constant. Total work done by the object in a motion is zero and hence the total energy is constant. Therefore, it is a conservative force.
Central force is the same as a centripetal force which is a force experienced on the object perpendicular to its velocity and undergoes a tangential force that tends to keep the object in a circular path.
When the force is applied to any object by being in physical contact with that body is known as a contact force, hence the central force can’t be a contact force.
Central force is when the force is subjected towards the center between the objects at a focus in a space. It is associated with the field or force of attraction between the objects separated by the distance.
Is electromagnetic force a central force?
An electromagnetic force is a central force.
A particle in the magnetic field moves along the direction perpendicular to the force which is responsible for a circular motion of the particle present in the field. The force acts towards the center of this circular path attained by the particle in motion.
Every object or entity exerts a contact or non-contact force on another object or entity. There are two distinct categories of forces; Contact forces and non-contact forces. Here are some exert force examples of both types given below;
Frictional force is generated by an object’s interactions with a surface when it moves or attempts to move relative to it. Friction forces are divided into two types: rolling and stationary friction. The friction force typically opposes the motion of an item; however, this is not always the case. When a book slides across the face of a desk, the furniture creates friction in the reverse way of the book’s motion. Friction is caused by the close proximity of two surfaces, which creates intermolecular attractive interactions between molecules from distinct surfaces.
As a result, friction is determined by the nature of the two surfaces and how tightly they are forced together. The equation below may be used to determine the highest amount of friction force that a material can exert on an object:
Ffrict=μ. Fnorm
Tension force
The tension force is carried via the string, rope, cable, wire or another similar device by pulling it tightly by both ends. The fact that tension force can only pull, not push does not make any difference. We normally presume that the tension in a cable is constant throughout the length of the wire.
Normal force
It’s a force that occurs when two surfaces come into touch with one another or it is the supporting force applied to a body that is in contact with another steady body. It always works out of the surface or perpendicular to the surface. It’s derived from the tiny displacement of molecules that mimics a spring system.
The normal force is the supporting force applied to a body in contact with another body that is steady. For example; When a book is rested on a material, that surface is applying an upward force on the book in order to sustain its mass. When a person leans against a wall, the wall pulls horizontally on the person. A normal force is sometimes exerted horizontally between two objects in touch with one other.
Air resistance forces
Air resistance force is the force that operates in the opposing direction of motion through a gas. It’s caused by a series of interactions with air molecules. It rises in lockstep with the rate of change in gas velocity. It also gets bigger when the region perpendicular to the motion gets bigger. The ability of air reluctance to obstruct an object’s motion is widely observed.
This power is sometimes neglected due to its tiny magnitude (because of this fact it is mathematically difficult to predict its value). It is especially visible in items that move at great velocities (e.g., a skydiver or a downhill skier) or have enormous surface areas (e.g., a skydiver or a downhill skier).
Applied forces
An applied force is a force that a person or another object applies to an entity or it is a force because of the movement of muscle mass. Muscle force is another name for it.. When a person pushes a desk across the room, the desk is subjected to an applied force. The applied force is the force that the person exerts on the desk.
Spring force
The force produced by a squeezed or extended spring on any item attached to it is known as the spring force. The dislocation of molecules provides spring force. It is constantly contrary to the displacement of spring. A pressure always acts on an item that compresses or extends a spring, restoring the item to its rest or balance state. The size of the force is precisely related to the degree of stretch or compression of most springs (particularly, those that are claimed to satisfy “Hooke’s Law”).
A force formed by action at a distance is the gravitational force. Even though the sun and other planets are separated by a great distance, the sun and planets exert a pull on each other. This interaction between the sun and the other planets is likewise an example of force-producing from afar.
Even when we move and our feet leave the earth’s surface and are no longer in contact with it, a gravitational pull exists between our feet and the Earth. According to the definition, it is the entity’s weight. All entities on Earth are subject to a gravitational pull that is directed “downward” towards the earth’s core. On Earth, the gravitational force is always equal to the object’s weight.
Electromagnetic force
The electromagnetic force is responsible for the linking of atoms and the form of materials. It is made up of basic electric and magnetic contacts. Electric forces act at some distance. Protons inside the nucleus and electrons outside the nucleus experience a force of attraction after a minimal distance difference. Magnetic forces, on the other hand, are action-at-a-distance forces. Despite being separated by only a few millimeters, two magnets may exert a magnetic pull on each other.
Weak nuclear force
The susceptible nuclear force reasons sure radioactive decay procedures and sure reactions the various maximum essential particles.
Strong nuclear force
The sturdy pressure operates the various essential particles and is liable for binding the nucleus together.
Difference between exert force examples
Let us find out the difference between contact force and non-contact force and the cause of different forces to exert. If two interacting objects that are exerting force on each other have physical touch or not, it distinguishes two types of forces from each other.
Contact forces:when two interacting objects are in physical touch with each other, contact forces occur. “Frictional forces, tensional forces, normal forces, air resistance forces, and applied forces are all examples of contact forces”
Non-contact forces:This type of force is experienced when two objects are not bodily engaged with each other but can still impose a push or pull regardless of their bodily separation. Gravitational force, Electromagnetic force, Weak nuclear force, Strong nuclear force are example of non contact forces.
How forces arise?
Due to interaction of two objects
Force is a push or pull and it takes place due to interaction of two objects. This interaction can be bodily touching or without physical touch. On the basis of this interaction forces are put in two different categories
How to find force?
Force can be calculated by newton’s second law of motion that is F=ma
The dynamic technique of measuring force uses a stretched spring to apply acceleration to a typical object. Although useful for defining things, it isn’t necessarily the most practical approach to quantify forces. (Acceleration is difficult to quantify.) Another approach for evaluating forces is to measure the change in form or size of a body (such as a spring) on which the force is exerted when the body is not moving.
The static technique of force measurement is what it is termed. The stationary approach is founded on the idea whenever a body encounters zero acceleration as a result of numerous forces, the vector sum of all forces operating on it must likewise be zero. This is, in reality, merely the second law of motion. A single force exerted on a body causes it to accelerate; this acceleration may be reduced to zero by applying a force of equal size but opposite direction on the body.
Are forces everywhere around us?
Yes, forces are everywhere around us.
To lift, turn, move, open, close, push, pull, and so on, forces are required. When you toss a ball, you are exerting effort on it to propel it into the air. An item can be affected by many forces at the same time.
Consider how many various forces you’ll need to ride your bike. Your feet press down on the pedals, your hands pull and push on the handlebars, and your body’s muscles keep you balanced. The tyres are rubbing up against the pavement, which is forcing them back. Wow, that’s quite a collection of forces!
A force is defined by its strength and direction
A force’s strength and direction are both essential
Soccer players use a specified amount of force to propel the ball in a specific direction when they kick the ball to another player. Forces have strength and direction at all times. Forces can be weak, as shown in the video when Zoe hits the golf ball weakly. A force can also be powerful, such as when Izzy slammed the ball into the ground. Forces, like people, have a sense of direction. The direction in which a rocket is fired must be carefully considered by rocket scientists. If even a minor mathematical error is made, the rocket’s trajectory will be thrown off, and the mission would fail.
Frequently asked questions |FAQs
Q. Can unbalanced forces change an object’s motion?
Unbalanced forces cause a body’s motion to vary.
There are two ways to accomplish this. The body will move if it is at rest and is pushed or pulled by an uneven force. Unbalanced forces canalso cause an item in motion to shift its speed or direction.
After losing a tug of war, a guy fall. A tug-of-war game is an excellent approach to demonstrate an imbalanced force. The game will be won if the participants on one side of the rope exert more force than the other. Another nice example is tug-of-war between you and your dog. When you let go of the toy while the dog is tugging on it, the dog will tumble backwards due to an uneven force.
Q. Balanced force does not cause shift in motion
Balanced forces are two forces that have the same strength but operate in different directions.
A guy and a lady pulling on a rope. Tug-of-war is an excellent illustration once more. The forces are balanced if the persons on each side of the rope are tugging with equal power but in opposing directions. As a result, there is no movement. Forces that are in balance can cancel each other out. The item does not move when there is a balanced force.
When studying the concept of motion and forces, it is important to understand the difference between net force and force. Force is a vector quantity that describes the push or pull on an object, while net force refers to the overall force acting on an object after considering all the individual forces. In simpler terms, net force takes into account the combined effect of all the forces acting on an object, resulting in either a balanced or unbalanced force. Understanding the distinction between net force and force is crucial in comprehending the motion and behavior of objects in various scenarios.
Key Takeaways:
Net Force
Force
Considers all the individual forces acting on an object
Describes the push or pull on an object
Can be balanced or unbalanced
Always has a magnitude and direction
Determines the acceleration of an object
Can change the motion of an object
Results from the vector sum of all the forces
Can be measured in Newtons (N)
Understanding the Concept of Force
Force is a fundamental concept in physics that plays a crucial role in understanding the behavior of objects in motion. It is defined as any interaction that can cause an object to accelerate, change its shape, or deform. In this article, we will explore the different types of forces and the role they play in motion.
Different Types of Forces
There are various types of forces that act on objects in different ways. Let’s take a closer look at some of the most common types of forces:
Gravity: Gravity is the force that attracts objects towards each other. It is responsible for keeping us grounded on the Earth and governs the motion of celestial bodies in space.
Friction: Friction is a force that opposes the motion of an object when it comes into contact with another surface. It can be helpful, like the friction between our shoes and the ground that allows us to walk, or it can be detrimental, like the friction that slows down a moving car.
Applied Force: An applied force is a force that is exerted on an object by a person or another object. For example, when you push a door open or kick a ball, you are applying a force to the object.
Tension Force: Tension force is the force transmitted through a string, rope, or cable when it is pulled tight. It is responsible for holding objects in place or causing them to move in a particular direction.
Normal Force: The normal force is the force exerted by a surface to support the weight of an object resting on it. It acts perpendicular to the surface and prevents objects from sinking into the ground.
The Role of Force in Motion
Force is directly related to the motion of an object. It can cause an object to start moving, stop moving, or change its direction. Understanding the role of force in motion is essential for comprehending the laws that govern the behavior of objects. Here are a few key points to consider:
Net Force: The net force is the vector sum of all the forces acting on an object. It determines the overall effect of the forces and whether the object will accelerate, decelerate, or remain at rest.
Balanced Forces: When the forces acting on an object are equal in magnitude and opposite in direction, they are considered balanced forces. In this case, the object will not accelerate and will remain in a state of equilibrium.
Unbalanced Forces: If the forces acting on an object are not equal, they are called unbalanced forces. Unbalanced forces cause the object to accelerate in the direction of the larger force.
Newton’s Laws of Motion: Newton’s laws of motion describe the relationship between force and motion. They provide a framework for understanding how forces affect the motion of objects.
To better understand the concept of force and its role in motion, force diagrams, calculations of force magnitude and direction, and examples of net force in different scenarios are often used. By analyzing these factors, we can determine the net force acting on an object and predict its motion accurately.
Remember, force is a fundamental concept in physics, and its understanding is crucial for comprehending the behavior of objects in motion. By exploring the different types of forces and their role in motion, we can gain a deeper insight into the fundamental principles that govern the physical world.
Understanding the Concept of Net Force
Net force is a fundamental concept in physics that helps us understand the motion of objects. It is the overall force acting on an object, taking into account both the magnitude and direction of all the individual forces acting upon it. By understanding net force, we can analyze and predict the motion of objects in various situations.
How Net Force is Calculated
To calculate the net force acting on an object, we need to consider all the forces acting upon it. Forces can be represented as vectors, which have both magnitude and direction. By adding up all the force vectors, we can determine the net force.
In the case of balanced forces, where the forces acting on an object are equal in magnitude and opposite in direction, the net force is zero. This means that the object will remain at rest or continue moving at a constant velocity.
On the other hand, when unbalanced forces act on an object, the net force is non-zero. This causes the object to accelerate in the direction of the net force. Newton’s second law of motion, F = ma, relates the net force to the acceleration of an object.
To better understand how net force is calculated, let’s consider an example. Imagine a box being pushed with a force of 10 N to the right and another force of 5 N to the left. The net force can be calculated by subtracting the force acting in the opposite direction:
Net force = 10 N – 5 N = 5 N to the right
In this case, the net force is 5 N to the right, causing the box to accelerate in that direction.
The Role of Net Force in Motion
Net force plays a crucial role in determining the motion of objects. It is responsible for causing changes in an object’s velocity, either by speeding it up or slowing it down. The direction of the net force determines the direction of the acceleration.
For example, consider a ball being thrown upwards. The force of gravity pulls the ball downwards, while the force applied by the person throwing the ball acts in the opposite direction. The net force is the difference between these two forces, and it determines whether the ball will continue to rise or start falling back to the ground.
In another scenario, imagine a team of people playing tug-of-war. Each team member exerts a force on the rope in an attempt to pull the opposing team towards them. The net force in this case is the sum of all the individual forces acting in the same direction. If the net force is greater on one side, that team will be able to pull the other team towards them.
By understanding net force, we can analyze and predict the motion of objects in various situations. It allows us to determine whether an object will remain at rest, move at a constant velocity, or accelerate in a particular direction.
In summary, net force is the overall force acting on an object, taking into account both the magnitude and direction of all the individual forces. By calculating the net force, we can determine the resulting motion of an object and understand the role it plays in various scenarios.
Comparing Force and Net Force
Is Net Force and Force the Same?
In the field of physics, force and net force are related concepts but they are not exactly the same. Force refers to a push or pull that acts upon an object, causing it to accelerate or deform. It is a vector quantity, meaning it has both magnitude and direction. On the other hand, net force is the vector sum of all the forces acting on an object. It takes into account both the magnitude and direction of each force to determine the overall effect on the object’s motion.
To understand the difference between force and net force, let’s consider an example. Imagine a box being pushed from two opposite sides by two people. Each person exerts a force on the box, but the net force is the combined effect of both forces. If the forces are equal in magnitude and opposite in direction, the net force will be zero, resulting in a balanced force. In this case, the box will remain at rest or continue moving at a constant velocity.
Difference Between Force and Net Force
The main difference between force and net force lies in their calculation and the consideration of multiple forces. Force can be calculated using the formulaF = ma, where F represents force, m represents mass, and a represents acceleration. On the other hand, net force takes into account all the individual forces acting on an object. It is calculated by summing up the vector components of each force.
To better understand the concept, let’s consider a scenario where a ball is being pulled by two teams in opposite directions. Each team exerts a force on the ball, but the net force is determined by subtracting the force exerted by one team from the force exerted by the other. If the forces are unbalanced, meaning one team exerts a greater force than the other, the net force will be in the direction of the stronger force. This will cause the ball to accelerate in that direction.
Does Net Force Change in Motion?
The net force acting on an object can change as its motion changes. According to Newton’s laws of motion, an object will remain at rest or continue moving at a constant velocity if the net force acting on it is zero. This is known as force equilibrium. However, if the net force is not zero, the object will experience acceleration in the direction of the net force.
For example, consider a ball rolling on a horizontal surface. Initially, the ball is at rest, and the net force acting on it is zero. When a force is applied to the ball, such as a kick, the net force becomes non-zero and the ball accelerates in the direction of the force. As the ball moves, other forces like friction and gravity may come into play, altering the net force and affecting the ball’s motion.
In summary, force and net force are related concepts in physics. Force refers to the push or pull acting on an object, while net force is the vector sum of all the forces acting on an object. Understanding the difference between force and net force is crucial in analyzing the motion of objects and predicting their behavior. By considering the magnitude and direction of forces, we can determine the net force and its impact on an object’s motion.
Specific Comparisons Between Net Force and Other Forces
Net Force Vs Applied Force
When comparing net force and applied force, it’s important to understand their individual roles in the physics of forces. Applied force refers to the force that is exerted on an object by another object or person. It is the force that is directly applied to an object to cause it to move or accelerate. On the other hand, net force is the vector sum of all the forces acting on an object. It takes into account both the magnitude and direction of the forces.
In terms of calculation, applied force can be determined by measuring the force applied to an object using a force sensor or by using the formulaF = ma, where F represents the applied force, m is the mass of the object, and a is the acceleration. Net force, on the other hand, is calculated by adding up all the individual forces acting on an object. It can be determined by considering the force vectors and their magnitudes and directions.
Net Force Vs Friction Force
Another important comparison is between net force and friction force. Friction force is the force that opposes the motion of an object when it is in contact with a surface. It acts in the opposite direction to the applied force and can vary depending on the nature of the surfaces in contact and the force with which they are pressed together. Net force, on the other hand, takes into account all the forces acting on an object, including the frictional force.
In terms of their effects on motion, friction force can cause an object to slow down or come to a stop if it is greater than the applied force. Net force, on the other hand, determines whether an object will accelerate, decelerate, or remain at a constant velocity. If the net force is zero, the object is said to be in a state of equilibrium, where the forces are balanced and there is no acceleration.
Net Force Vs Normal Force
The comparison between net force and normal force is also significant. Normal force is the force exerted by a surface to support the weight of an object resting on it. It acts perpendicular to the surface and prevents the object from sinking into or passing through the surface. Net force, on the other hand, considers all the forces acting on an object, including the normal force.
In terms of their relationship, the normal force is equal in magnitude but opposite in direction to the force exerted by the object on the surface due to gravity. This ensures that the object remains in equilibrium when resting on a surface. The net force, however, takes into account all the forces acting on the object, including the normal force, and determines the overall motion of the object.
Net Force Vs External Force
Lastly, let’s compare net force and external force. External force refers to any force that is exerted on an object by an external source, such as a person or another object. It can be applied in any direction and can cause the object to accelerate or change its motion. Net force, on the other hand, considers all the forces acting on an object, including the external force.
In terms of their effects on motion, the external force can cause an object to accelerate or change its direction. The net force, however, determines the overall motion of the object by considering the vector sum of all the forces acting on it. If the net force is zero, the object will remain at a constant velocity or in a state of equilibrium.
In summary, net force is a comprehensive measure of all the forces acting on an object, taking into account their magnitudes and directions. It is essential in understanding the motion and equilibrium of objects. By comparing net force with applied force, friction force, normal force, and external force, we can gain a deeper understanding of the dynamics of forces in the field of physics.
Understanding the Concept of Unbalanced Force
In the world of physics, forces play a crucial role in understanding the motion of objects. Forces can be classified into two main categories: balanced forces and unbalanced forces. Today, we will delve into the concept of unbalanced forces and explore how they differ from net forces.
To comprehend unbalanced forces, it is essential to first grasp the concept of net force. Net force refers to the overall force acting on an object, taking into account both the magnitude and direction of all the individual forces acting upon it. In simpler terms, it is the sum of all the forces acting on an object.
On the other hand, unbalanced forces occur when the net force acting on an object is not equal to zero. This means that there is an imbalance in the forces acting on the object, causing it to accelerate or decelerate in a particular direction. Unbalanced forces are responsible for changing an object’s state of motion.
To better understand the difference between unbalanced forces and net forces, let’s compare them using a table:
Unbalanced Forces
Net Forces
Causes acceleration or deceleration
Overall force acting on an object
Imbalance in forces
Sum of all individual forces
Changes an object’s state of motion
Determines the direction and magnitude of motion
Net Force or Unbalanced Force: A Comparison
Now that we have a basic understanding of unbalanced forces and net forces, let’s compare them in more detail:
Definition: Unbalanced forces cause acceleration or deceleration in an object, while net force refers to the overall force acting on an object.
Imbalance vs Sum: Unbalanced forces occur when there is an imbalance in the forces acting on an object, whereas net force is the sum of all the individual forces acting on an object.
Effect on Motion: Unbalanced forces change an object’s state of motion, either by speeding it up or slowing it down. Net force, on the other hand, determines the direction and magnitude of an object’s motion.
Calculation: Unbalanced forces can be calculated by considering the individual forces acting on an object and their respective magnitudes and directions. Net force is calculated by summing up all the individual forces acting on an object.
Examples: Unbalanced force examples include a person pushing a box, a team pulling a rope, or a ball rolling down a hill. Net force examples can be seen when multiple forces act on an object simultaneously, resulting in a single overall force.
In conclusion, unbalanced forces and net forces are closely related but have distinct characteristics. Unbalanced forces cause changes in an object’s motion, while net force represents the overall force acting on an object. Understanding these concepts is fundamental in comprehending the physics of forces and their impact on motion.
Understanding the Concept of Resultant Force
Net Force Vs Resultant Force
When it comes to understanding the concept of resultant force, it is important to differentiate between net force and resultant force. These terms are often used interchangeably, but they have slightly different meanings in the context of physics of forces.
Net Force Calculation
Net force refers to the overall force acting on an object. It takes into account the magnitude and direction of all the individual forces acting on the object. In other words, it is the vector sum of all the forces acting on an object. To calculate the net force, we need to consider both the magnitude and direction of each force.
Balanced Forces and Unbalanced Forces
In some cases, the forces acting on an object may be balanced, meaning that the net force is zero. This occurs when the forces are equal in magnitude and opposite in direction, resulting in a state of equilibrium. On the other hand, unbalanced forces occur when the net force is not zero, causing the object to accelerate in the direction of the resultant force.
Newton’s Laws of Motion
Understanding net force and resultant force is closely related to Newton’s laws of motion. According to Newton’s first law, an object at rest will remain at rest, and an object in motion will continue moving at a constant velocity, unless acted upon by an external force. This external force is the net force acting on the object.
Gravitational Force and Frictional Force
Two common types of forces that contribute to the net force are gravitational force and frictional force. Gravitational force is the force of attraction between two objects with mass, such as the force that pulls objects towards the Earth. Frictional force, on the other hand, opposes the motion of an object and depends on the nature of the surfaces in contact.
What is Net Force or Resultant Force?
Net force, also known as resultant force, is the vector sum of all the forces acting on an object. It represents the overall effect of these forces and determines the resulting motion of the object. The net force takes into account both the magnitude and direction of each force, resulting in a single force that represents the combined effect.
To better understand net force, let’s consider an example. Imagine a team of people playing tug-of-war. Each person exerts a force on the rope, either pulling towards their side or trying to keep the rope in the middle. The net force in this scenario is the vector sum of all the individual forces. If the forces pulling towards one side are greater than the forces pulling towards the other side, the net force will be in the direction of the stronger team.
In physics, net force is often represented using force diagrams, where arrows indicate the magnitude and direction of each force. By analyzing these diagrams, we can determine the net force acting on an object and predict its resulting motion.
To calculate the net force, we need to consider the force components in different directions. For example, if a box is being pushed with a force of 10 N to the right and experiencing a frictional force of 5 N to the left, the net force can be calculated by subtracting the force opposing motion from the force causing motion. In this case, the net force would be 5 N to the right.
Understanding net force is crucial in understanding the relationship between force and motion. By analyzing the net force acting on an object, we can determine whether it will accelerate, decelerate, or remain at a constant velocity.
Remember, net force is the combined effect of all the forces acting on an object. It takes into account both the magnitude and direction of each force, allowing us to determine the resulting motion.
Understanding the Concept of Average Force
In physics, the concept of average force is an important aspect of understanding the behavior of objects in motion. It allows us to determine the overall effect of multiple forces acting on an object over a certain period of time. By calculating the average force, we can gain insights into the net force experienced by an object and how it affects its motion.
To grasp the difference between net force and average force, let’s delve into their definitions and applications. Net force refers to the vector sum of all the forces acting on an object. It takes into account both the magnitude and direction of each force. By calculating the net force, we can determine whether the forces acting on an object are balanced or unbalanced.
On the other hand, average force is the total force exerted on an object divided by the time interval over which the forces act. It provides us with an understanding of the overall effect of the forces on the object during a specific period. Average force is particularly useful when dealing with varying forces or forces that change over time.
To illustrate the difference between net force and average force, let’s consider an example. Imagine a team of people pulling a box with ropes from different directions. Each person exerts a force on the box, but the net force is the vector sum of all these forces. If the forces are balanced, the net force will be zero, and the box will remain at rest or continue moving at a constant velocity.
However, if the forces are unbalanced, the net force will be nonzero, causing the box to accelerate in the direction of the resultant force. In this scenario, the average force will give us an idea of the overall effect of the forces exerted by the team over a specific time interval.
Average Force Vs Net Force
Now, let’s explore the relationship between average force and net force in more detail. Average force is calculated by dividing the total force exerted on an object by the time interval during which the forces act. It provides us with an understanding of the average effect of the forces on the object’s motion.
On the other hand, net force takes into account the vector sum of all the forces acting on an object. It considers both the magnitude and direction of each force to determine the overall effect on the object’s motion. Net force is particularly useful when analyzing the acceleration or deceleration of an object.
To better understand the difference between average force and net force, let’s consider the example of a ball being thrown vertically upwards. When the ball is thrown, it experiences a gravitational force pulling it downwards and an applied force propelling it upwards. The net force acting on the ball is the difference between these two forces.
As the ball moves upwards, the gravitational force and the applied force gradually decrease until they become equal at the highest point of the ball’s trajectory. At this point, the net force is zero, and the ball momentarily comes to a stop before falling back down due to the force of gravity. The average force during the entire motion of the ball can be calculated by considering the total force exerted on the ball divided by the time it takes for the ball to complete its trajectory.
In summary, understanding the concept of average force is crucial in analyzing the motion of objects. By distinguishing between net force and average force, we can gain insights into the overall effect of forces on an object’s motion and determine whether the forces are balanced or unbalanced. This knowledge allows us to apply Newton’s laws of motion effectively and comprehend the relationship between force and motion.
Understanding the Concept of Balanced and Total Force
In the world of physics, forces play a crucial role in determining the motion of objects. To comprehend the dynamics of forces, it is essential to understand the concepts of balanced and total force. These concepts help us analyze the effects of different forces acting on an object and predict its resulting motion.
Net Force Vs Balanced Force
When multiple forces act on an object, the net force is the vector sum of all the individual forces. It represents the overall force that influences the object’s motion. If the net force on an object is zero, the forces are said to be balanced. In this scenario, the object remains at rest or continues to move with a constant velocity. Balanced forces occur when the magnitudes and directions of the forces cancel each other out, resulting in a state of equilibrium.
Is Net Force Total Force?
While the net force represents the combined effect of all the forces acting on an object, it is important to note that it may not always be the same as the total force. The total force refers to the sum of all the forces acting on an object, regardless of their canceling or reinforcing effects. In some cases, the total force may be zero, indicating a state of equilibrium. However, in other situations, the total force may be nonzero, resulting in an unbalanced force and causing the object to accelerate.
Net Force Vs Total Force
The distinction between net force and total force lies in their definitions and implications. Net force takes into account both the magnitudes and directions of the individual forces, resulting in a single force that represents their combined effect. On the other hand, total force refers to the sum of all the forces acting on an object, regardless of their canceling or reinforcing effects. While the net force determines the object’s acceleration or deceleration, the total force provides a comprehensive understanding of all the forces at play.
Total Force Vs Net Force
To further illustrate the difference between total force and net force, let’s consider an example. Imagine a team of people playing tug-of-war with a box. Each team member exerts a force on the rope, either pulling or pushing. The total force in this scenario would be the sum of all the individual forces applied by the team members. However, the net force would be the vector sum of these forces, taking into account their magnitudes and directions. The net force determines whether the box moves, remains stationary, or accelerates in a particular direction.
In summary, understanding the concepts of balanced and total force is crucial in analyzing the effects of forces on objects. By considering the net force and total force, we can determine whether an object will remain at rest, move with a constant velocity, or accelerate. These concepts, rooted in Newton’s laws of motion, provide a foundation for comprehending the physics of forces and their impact on motion.
The Impact of Net Force
In the world of physics, forces play a crucial role in determining the motion and behavior of objects. One important concept in this realm is the net force, which refers to the overall force acting on an object. Understanding the impact of net force is essential in comprehending the principles of motion and acceleration.
Does Net Force Cause Acceleration?
When it comes to the relationship between net force and acceleration, the two are closely intertwined. According to Newton’s second law of motion, the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass. In simpler terms, the greater the net force applied to an object, the greater its acceleration will be. Conversely, if the net force is reduced or eliminated, the object’s acceleration will decrease or come to a halt.
To better grasp the concept, let’s consider an example. Imagine a box being pushed with a certain force. If the force applied in one direction is greater than any opposing forces, such as friction, the box will experience a net force in the direction of the applied force. As a result, the box will accelerate in that direction. On the other hand, if the opposing forces are equal to or greater than the applied force, the net force will be zero or negative, causing the box to either remain at rest or decelerate.
Does Net Force Cause Motion?
The impact of net force on motion is undeniable. Net force is responsible for initiating and maintaining the motion of an object. When a net force acts on an object, it imparts an acceleration, causing the object to move in the direction of the force. This motion will continue until another force acts upon the object, altering its net force and potentially changing its direction or speed.
To illustrate this, let’s consider the example of a ball being thrown into the air. When the ball is released, the force of gravity acts upon it, pulling it downward. However, if an upward force is applied to the ball, such as when it is thrown, the net force becomes the difference between the upward and downward forces. As a result, the ball accelerates upward, defying gravity. Once the ball reaches its peak height, the net force becomes zero, and gravity takes over, causing the ball to decelerate and eventually fall back to the ground.
In summary, net force is a fundamental concept in physics that influences the motion and acceleration of objects. By understanding the physics of forces, net force calculation, and the principles of Newton’s laws of motion, we can comprehend how net force affects the behavior of objects in various scenarios. Whether it’s the gravitational force acting on a falling object or the frictional force opposing the motion of a sliding box, the net force determines the direction and magnitude of an object’s acceleration. So, the next time you observe an object in motion, take a moment to consider the net force at play and appreciate the intricate relationship between force and motion.
Conclusion
In conclusion, net force and force are two important concepts in the field of physics. While force refers to the push or pull on an object, net force takes into account the combined effect of all the forces acting on an object. Net force is the vector sum of all the individual forces, and it determines the overall motion of an object. If the net force is zero, the object will remain at rest or continue moving with a constant velocity. On the other hand, if the net force is non-zero, the object will experience acceleration and its motion will change. Understanding the difference between net force and force is crucial for comprehending the dynamics of objects in motion.
How can the concepts of net force and force be used to calculate speed from force and mass?
Calculating speed from force and mass is a fundamental concept in physics. By understanding the relationship between net force and force, we can determine the speed of an object. Net force is the total force acting on an object, and it can be calculated by adding up all the individual forces. On the other hand, force is the interaction that causes an object to accelerate or change its momentum. By using the formula F = ma, where F is the net force, m is the mass of the object, and a is the acceleration, we can determine the force exerted on an object. Once we have the force and mass, we can then calculate the speed using the formula v = sqrt(2F/m), where v is the speed. To learn more about calculating speed from force and mass, visit Calculating speed from force and mass.
Frequently Asked Questions
What is the difference between net force and resultant force?
Net force and resultant force essentially refer to the same concept. Both terms describe the sum of all forces acting on an object. However, the term‘resultant force‘ is often used in the context of vector addition, where forces are combined considering their magnitudes and directions.
How does net force differ from friction force?
Net force is the total force acting on an object after all forces are combined, considering their direction and magnitude. On the other hand, friction force is a specific type of force that opposes the motion of an object. It is just one component that could contribute to the net force.
Does net force change in motion?
Yes, net force can change during motion. If the forces acting on an object change in magnitude, direction, or both, the net force will change. This can result in a change in the object’s speed, direction, or both, according to Newton’s second law of motion.
Is net force and force the same?
No, net force and force are not the same. A force refers to any interaction that, when unopposed, will change the motion of an object. Net force, however, is the vector sum of all the forces acting on an object.
What does it mean by net force or unbalanced force?
Net force or unbalanced force refers to the total force acting on an object when all the individual forces have been combined. If the net force is zero, the forces are balanced and the object remains at rest or continues moving at a constant velocity. If the net force is not zero, the forces are unbalanced, and the object’s motion will change.
How does the magnitude of net force relate to net force?
The magnitude of net force is the size or amount of the net force, disregarding its direction. It is a scalar quantity, unlike net force, which is a vector quantity that includes both magnitude and direction.
What is the difference between force and net force?
A force is any interaction that changes the motion of an object when unopposed. Net force, on the other hand, is the total force acting on an object when all the individual forces have been combined. It considers both the magnitude and direction of all the forces.
How does net force compare to balanced force?
A net force implies that the forces acting on an object are unbalanced, resulting in a change in motion. On the other hand, balanced forces mean that the net force is zero, and there is no change in the object’s motion.
What is the difference between average force and net force?
Average force is the total force exerted on an object over a period of time, divided by that time interval. Net force, however, is the vector sum of all the forces acting on an object at a specific moment.
Does net force cause motion?
Yes, a net force acting on an object causes it to accelerate, and this change in velocity means the object is in motion. According to Newton’s second law of motion, the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass.
When it comes to understanding the interaction between two blocks, the concept of normal force plays a crucial role. The normal force is the force exerted by a surface to support the weight of an object resting on it. In the case of two blocks in contact, the normal force is the force exerted by one block on the other perpendicular to the contact surface. In this blog post, we will explore how to find the normal force between two blocks, considering various factors such as friction, gravity, mass, and weight.
Identifying the Variables
Before diving into the calculations, let’s familiarize ourselves with the variables involved in finding the normal force between two blocks.
m1 and m2: The masses of the two blocks, respectively.
g: The acceleration due to gravity (approximately 9.8 m/s^2).
N: The normal force between the two blocks.
F_applied: Any externally applied force on the system.
F_friction: The force of friction between the blocks, if present.
Applying the Formula for Finding Normal Force
To calculate the normal force between two blocks, we need to consider the forces acting on the system. Newton’s second law of motion states that the sum of all forces acting on an object is equal to the mass of the object multiplied by its acceleration. In this case, we can apply Newton’s second law to the system of two blocks.
The formula for finding the normal force can be derived from Newton’s second law as follows:
Here, represents the sum of all forces acting on the system, is the total mass of the system is the acceleration of the system.
Since we want to find the normal force between the two blocks, we can rearrange the equation to solve for :
Worked Out Example: Calculating Normal Force
Let’s consider an example to illustrate how to calculate the normal force between two blocks. Suppose we have two blocks with masses of 2 kg and 3 kg, respectively, resting on a frictionless surface. An external force of 20 N is applied to the system.
To find the normal force, we can follow these steps:
Calculate the total mass of the system: .
Determine the acceleration of the system: Since there is no friction or any other external force acting on the blocks horizontally, the acceleration is zero ).
Substitute the values into the formula to calculate the normal force: .
In this example, the negative value of the normal force indicates that the blocks are being pushed against each other, rather than being pulled apart.
Factors Affecting the Normal Force Between Two Blocks
Now that we know how to calculate the normal force, let’s explore the factors that can affect its magnitude.
The Role of Friction in Determining Normal Force
When there is friction between the two blocks, the force of friction affects the normal force. The force of friction opposes the relative motion between the blocks and depends on the coefficient of friction ) and the normal force itself. The formula for calculating the force of friction is:
Where is the coefficient of friction.
The Impact of Gravity on Normal Force
The gravitational force acting on each block contributes to the normal force between them. The weight of each block creates a downward force due to gravity. The formula for calculating weight is:
Where is the mass of the block and is the acceleration due to gravity.
The Effect of Mass and Weight on Normal Force
The mass and weight of the blocks also affect the normal force between them. As the mass or weight of the blocks increases, the normal force also increases. This is because the weight of the blocks creates a downward force that must be balanced by the normal force.
Advanced Concepts Related to Normal Force
Let’s explore a few advanced concepts related to the normal force between two blocks.
Understanding the Normal Reaction Between Two Blocks
The normal force can also be referred to as the normal reaction. It is called a reaction because it is a force that acts in response to another force (in this case, the weight of the blocks). The normal force is always perpendicular to the contact surface between the blocks.
How to Calculate the Tension Between Two Blocks
In situations where the two blocks are connected by a rope or a string, it is possible to calculate the tension between them. The tension is the force transmitted through the rope or string and is equal in magnitude to the normal force between the blocks. By calculating the normal force, we can determine the tension in the rope or string.
Worked Out Example: Finding Contact Force Between Two Blocks Without Friction
Suppose we have two blocks with masses of 4 kg and 6 kg, respectively, resting on a frictionless surface. An external force of 30 N is applied to the system.
To find the contact force between the two blocks (which is equivalent to the normal force), we can follow these steps:
Calculate the total mass of the system: .
Determine the acceleration of the system: Since there is no friction or any other external force acting on the blocks horizontally, the acceleration is zero ).
Substitute the values into the formula to calculate the normal force: .
In this example, the negative value of the normal force indicates that the blocks are being pushed against each other.
By understanding the concepts and formulas related to normal force, we can analyze and predict the behavior of blocks in various scenarios. Whether it’s calculating the normal force in a simple system or considering the impact of friction and gravity, mastering this concept is essential for understanding the physics of objects in motion.
Now that you have a solid understanding of how to find the normal force between two blocks, you can apply these concepts to a wide range of scenarios. Remember to consider factors such as friction, gravity, mass, and weight when calculating the normal force.
How does the concept of finding the normal force between two blocks relate to the idea of “Finding coefficient of kinetic friction”?
To understand how the concept of finding the normal force between two blocks intersects with the idea of “Finding coefficient of kinetic friction,” it is essential to consider the relationship between these two factors in a physics problem. The normal force is the perpendicular force exerted by a surface to support an object in contact, while the coefficient of kinetic friction represents the frictional force between two surfaces in relative motion. By determining the normal force, one can then calculate the coefficient of kinetic friction, as shown in the article “Finding coefficient of kinetic friction”. This article provides a comprehensive guide on how to calculate the coefficient of kinetic friction using various methods, which can be beneficial in scenarios where the normal force between two blocks is involved.
Numerical Problems on How to Find Normal Force Between Two Blocks
Problem 1:
Two blocks, A and B, are placed on top of each other on a horizontal surface. Block A has a mass of 5 kg and block B has a mass of 8 kg. The coefficient of friction between block A and the surface is 0.3, while the coefficient of friction between block B and block A is 0.2. Determine the normal force between the two blocks.
Solution:
Given:
– Mass of block A, kg
– Mass of block B, kg
– Coefficient of friction between block A and the surface,
– Coefficient of friction between block B and block A,
To find the normal force between the blocks, we need to consider the forces acting on each block individually.
For block A:
The weight of block A, , where is the acceleration due to gravity.
The normal force on block A, , is equal and opposite to the weight, so .
The friction force acting on block A, , can be determined using the equation .
For block B:
The weight of block B, .
The friction force acting on block B, , can be determined using the equation .
Since the two blocks are in contact with each other, the normal force acting on block B is equal to the friction force acting on block A, i.e., .
Now, let’s calculate the normal force on block A:
Substituting the given values:
Finally, we can calculate the normal force on block B:
Substituting the given values:
Calculating :
Hence, the normal force between the two blocks is .
Problem 2:
Two wooden blocks, P and Q, are placed on a table. Block P has a mass of 10 kg and block Q has a mass of 5 kg. The coefficient of friction between block P and the table is 0.4, while the coefficient of friction between block Q and the table is 0.3. Determine the normal force between the two blocks.
Solution:
Given:
– Mass of block P, kg
– Mass of block Q, kg
– Coefficient of friction between block P and the table,
– Coefficient of friction between block Q and the table,
To find the normal force between the blocks, we need to consider the forces acting on each block individually.
For block P:
The weight of block P, , where is the acceleration due to gravity.
The normal force on block P, , is equal and opposite to the weight, so .
The friction force acting on block P, , can be determined using the equation .
For block Q:
The weight of block Q, .
The friction force acting on block Q, , can be determined using the equation .
Since the two blocks are in contact with each other, the normal force acting on block Q is equal to the friction force acting on block P, i.e., .
Now, let’s calculate the normal force on block P:
Substituting the given values:
Finally, we can calculate the normal force on block Q:
Substituting the given values:
Calculating :
Hence, the normal force between the two blocks is .
Problem 3:
Two blocks, X and Y, are connected by a string passing over a frictionless pulley. Block X has a mass of 6 kg and is on a horizontal surface, while block Y has a mass of 4 kg and is hanging vertically. Determine the normal force between the two blocks.
Solution:
Given:
– Mass of block X, kg
– Mass of block Y, kg
To find the normal force between the blocks, we need to consider the forces acting on each block individually.
For block X:
The weight of block X, , where is the acceleration due to gravity.
The normal force on block X, , is equal and opposite to the weight, so .
For block Y:
The weight of block Y, .
The tension in the string, , is equal and opposite to the weight, so .
Since the two blocks are connected, the normal force acting on block Y is equal to the tension in the string, i.e., .
Now, let’s calculate the normal force on block X:
Substituting the given values:
Finally, we can calculate the normal force on block Y:
Substituting the given values:
Hence, the normal force between the two blocks is .
In this article, we are going to discuss what is muscular force, is muscular force a contact force or a non-contact force, the reason, and some facts.
Muscular force is a force imposed on any object by using the muscles strength of the body. It is a contact force as it acts only when the two bodies are in physical contact with each other.
Contact Force
A force is called a contact force when the force applied on the body is in physical contact with the body applying force. Examples of the contact forces are, man lifting a weight, pushing a trolley, object flying in the air dragged by the air resistance, frictional force on the tyres of the car accelerating on the metallic road, etc. No field is linked with these kinds of forces and acts only when the object is in physical contact with another object on which the force is supposed to act.
Non-contact Force
A force is known to be a non-contact force when the force is applied to the object without being in physical contact with it. These types of forces are associated with a field, and the forces are exerted on another body when present in this field region. Examples are the attraction of the iron nail on the bar magnet, deflection of the magnetic needle in the compass on the influence of the magnetic field of the Earth, the motion of the charges in the electric field, raindrops falling on the ground, etc.
What is Muscular Force
The physical force applied to any object by using muscle strength is called the muscular force.
Some examples of the muscular forces are player kicking a football, riding a bicycle, playing badminton, weight lifting, walking, pulling a trolley bag, climbing stairs, doing pushups on the ground, running, etc.; all these are the physical activities that involves using some muscles of the body and hence, it is called muscular force.
Why Muscular Force is a Contact Force
The human or an animal can move and do the work because of the muscular force that is utilized for every activity.
The work is done using a muscle strength of a body that results due to the contraction of the muscles. The muscles contract to create a movement of a body to exert a force on the object. The force thus applied is a muscular force. The muscular force comes into context only when the physical body comes in contact with the object and applies a force on it, and hence the muscular force is a contact force.
How does Muscles Generate Force
For every activity to be performed, different muscular strength is required to get the activity done. For example, if you bought a stack of books from the library and then lift a single book from the bunch of books to read it. The force required to lift the bunch of books was much greater than the force to take out a single book from it. The heavier the mass, the greater is the force experienced, and hence more is muscular force applied.
Little boy carrying a stack of books; Image credits: classroomclipartLittle boy lifting a single book from the stack of books; Image credit: istockphoto
While applying a muscular force on the object, the muscle contracts causing the muscles to shorten, thereby building enough potential energy that generates the force. If the force experienced from the opposite direction is greater than the applied muscular force, then the muscles contraction will be more.
The muscle contraction is concentric or eccentric depending upon the arms or legs moment. The concentric contraction led to the shortening of the muscles and eccentric contraction causes the muscles to elongate.
On what factors does the muscular force depend
The muscular force can be controllable or uncontrollable depending upon the activity and the object on which the force is applied. The heavier the mass of the object, the greater is the muscular force required to be subjected on the object. Lighter the mass, very small muscular strength is utilized. Depending upon the mass of the object, and the object that needs to be displaced the force is applied to the object.
Muscular force is directly proportional to the muscular strength the body possesses. If a woman having a weight of 60kg can lift a weight of 20kg, the same weight is supposed to be lifted by the girl with a bodyweight 35kg, then she will have to put enough muscular strength to lift the weight; because the lady with 60kg has more muscular strength than the girl with 35kg; hence we can say that muscular strength is directly proportional to the mass.
The more the strength of the muscle, the more is the ability of a person or an animal to lift or move the object.
The force imposed on the object due to the movement of the arm results in the torque. Torque experienced on the object due to the muscular force is given as the product of the force and the arm moment and is formulated as
Where tau (t) is a torque experienced on the object due to arm movement
F is a force on the object
mA is a mass
The muscular force depends upon the muscular strength of the body. The greater the contraction of the muscle, the greater it will release the force required to accomplish the activity.
A frictional force acts on the objects in motion that acts in a direction opposite to the direction of the motion of the object. Friction resists the motion of a body when it is in close contact with another body, hence it is a contact force.
The muscular force is also a contact force. The frictional force will come into consideration only when the muscular force applied will be ascertained to resist the motion of the object. Hence, a muscular force can be a frictional force too.
Why muscular force is not a non-contact force?
When a force is applied on the body without being in physical contact with the body is known as the non-contact force.
The muscular force is the force applied by the muscles when doing any work only by making close contact with the body. The force is applicable only when the body is in close physical contact with the object. It is not associated with any field that the disturbance created in the field will get the work done. Hence, muscular force is not a non-contact force, but it is a contact force.
What force is a muscular force?
A muscular force is a contact force that comes into action by utilizing muscle power.
The force applied on the object using muscle power is a muscular force. While riding a bicycle the muscular force is applied for peddling the wheels to keep the bicycle in momentum, and brakes are applied by pulling the brake pad and a bell is the rung is by using the hand muscular strength. The man pushing a box with load, the batsman hitting a ball, are also examples of a muscular force.
In this article, we are going to discuss is gravitational force a contact force or a non-contact, why is gravity a non contact force, the reasons, and some facts.
A gravitational force is a force of attraction exerted by two bodies on each other and is a non-contact force between the two objects.
What is a Gravitational Force
The gravitational force is one of the four fundamental forces in nature and is the weakest force of attraction than the electromagnetic force, strong force, and weak force.
The gravitational force is a force of attraction between the two bodies having mass and separated by a distance ‘r’. The gravitational force is known to be an attractive force because it is exerted equally and opposite by the two objects on each other that keeps them binding in an orbit. Such that objects with less mass will tend to orbit around the heavier body, while both the objects with equal masses will revolve in the same orbit with respect to each other.
The idea of gravitational force was thought of first by the famous scientist Newton and he stated the law of gravity which says that “The gravitational force between the two bodies is proportional to the product of the two masses and inversely proportional to the square of the distance between them”. It is formulated as
F=G*(m1m2)/r2
Where G is a gravitational constant G=6.67*10-11
R is the distance of separation between two objects with mass
The same is illustrated for point charges in the electric field. The electric force experienced by two point charges q1 and q2 separated by a distance ‘r’ is given by
Where
is a Coulomb’s constant.
Characteristics of the Gravitational Force
It is the weakest force of all the fundamental forces in nature.
It is an attractive force held between two bodies that keep them bounded with each other.
It is a non-contact force that is exerted on the body from the distance separated from each other.
No field is required for two bodies to exert force on each other.
It is a long-range force. For example, the moon orbiting around the Earth is due to the gravitational pull of the Earth, the planets revolving around the Sun, the high tides and low tides on the Earth due to the gravitational pull of the Moon on the Earth.
The gravitational force depends upon the masses of the two object exerting force on each other.
The gravitational force decrease to the square times the length separating the objects as the distance between them increases.
The gravitation constant ‘G’ value is constant on the Earth.
Why is Gravity a Non-Contact Force
In Latin, gravity means ‘weight’. The gravitational force exerted on every object surrounding the Earth is known as gravity.
Have you ever wondered if there was no gravity of the Earth then what would have happened? We would have just floated in the air, not able to walk on the surface. The Earth in the orbit would have revolved at a faster rate around the Sun, all the objects would have just freely drifted in the atmosphere, we would have not been able to drive any vehicles, and trees would have not grown on the ground and so many things…
The world is as it is, is only because of the Earth’s gravity, this solar system exists only because the gravitational attraction exerted by the Sun is far stronger than any other object in this system.
The force exerted by the Earth on the objects surrounding it is due to the Earth’s gravitation force and the same is formulated as given below:
Where G is a gravitational constant
ME is the mass of the Earth
M is a mass of the object
RE is the radius of the Earth
h is an altitude above the surface of the Earth, if the object is on the surface of the Earth then h = 0.
If the object is present at infinity then it is concluded from the above expression that the force vanishes at the largest distance.
According to Newton’s Second Law of motion, “The acceleration of the object depends upon the net force acting on it and the mass of the object, the acceleration of the body is directly proportional to the force acting on it and inversely proportional to the mass of the object” and is represented as F=ma. The greater the mass of the object, the less is its acceleration.
Comparing the equation of gravity due to earth and Newton’s 2nd law of motion, we have
‘g’ is an acceleration due to the gravity of the Earth and it is constant on the Earth except at the magnetic poles of the Earth because the magnetic strength of the Earth is higher at the pole hence the ‘g’ value is slightly increased to 10m/s2.
Due to gravity, the weight of any object on the planet Earth will be mass times the acceleration due to gravity (Weight=Mass´g). The work done by the gravitational pull of the Earth on the object is
Gravity is said to be a non-contact force because the gravitational force is exerted by one mass on another from the distance separated between them and without being in physical contact. All the objects having mass are bounded to one another by the gravitational pull of attraction. Gravity is a central force because it is directed towards the center of the objects.
How Gravitational Force is Non-Contact Force
All the objects with masses show some gravitational force which varies with respect to the distance of separation between two objects into consideration joint by a single line. The force experienced by both the objects on one another is the same.
Ball in the air experiences a gravitational force
Have you ever noticed when the ball is thrown in the air, it will stop accelerating for very finite milli-seconds when it is reached at its highest peak and then the speed of the ball will exponentially increase until it bounces the ground? At the peak, the ball gains the potential energy and is gradually converted into kinetic energy and a ball accelerates at faster rates, because the gravitational force on the ball increases with decreasing distance. The distance covered by the ball while approaching the ground is a square time of the distance elapsed by it.
Well, the gravitational force is a force between the Earth and the ball, the force exerted by each are equal in magnitude and acts in an opposite direction. Farthest the body, less is the gravitational force experienced on each other.
Unit of Gravitational force
The unit of gravitational force is Newton, named after the scientist Isaac Newton for his discovery.
The universal gravitational constant G has a value 6.67*10-11 N.m2/kg2. Substituting this in a gravitational force formula in CGS unit we gets
Hence, the unit of the gravitational force is Newton.
What is the gravitational force between the Earth and the Sun?
Because of the presence of the gravitational pull between the Earth and the Sun, the Earth revolves in an orbit around the Sun.
We know:
The mass of the Earth ME= 6*1024
The mass of the Sun Ms= 2*1030
The distance between the Earth and the Sun d= 1.5*1011
The gravitational constant G = 6.67*10-11
Therefore,
The gravitational force between the Sun and the Earth is approximately
What is the gravitational force between the Sun and Jupiter?
Planet Jupiter is the largest juvenile planet in our solar system and it pulls all the terrestrial bodies approaching our planet Earth.
The mass of the Jupiter M= 1.9*1027 kg
The mass of the Sun Ms= 2*1030 kg
The distance between the Sun and Jupiter is d = 7.8*1011 m.
Therefore, the gravitational force between the Sun and the Earth is approximately 42*1022
The gravitation force between the Sun and Jupiter is more than the gravitation force between the Earth and the Sun is because the mass of the planet Jupiter is much greater than that of the Earth.
How are the satellites launched in space?
The satellites are launched into space on rockets with tons of propellant to produce enough trust to boost away from the Earth’s atmosphere.
Once the rocket reaches a particular distance in space, from where there are no chances of a satellite falling back into the Earth’s atmosphere or returning back on the Earth, the rocket will release the satellite into the space or an orbit of any planet on which the studies are to be carried out.The satellite takes the momentum from the rocket to enter the orbit of the planet. The gravity of the planets attracts the satellite towards it while the momentum of the satellite acts perpendicular to the direction of the gravity which keeps the satellite in motion and revolves around the planets in an orbit.
represents the sum of all forces acting on the system, 
is the total mass of the system 
is the acceleration of the system.
:
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) and the normal force itself. The formula for calculating the force of friction is:
is the coefficient of friction.
is the mass of the block and 
is the acceleration due to gravity.
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.
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, where 
, is equal and opposite to the weight, so 
.
, can be determined using the equation 
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on block B:
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.
.
, can be determined using the equation 
.
.
on block Q:
kg
kg
, where 
, is equal and opposite to the weight, so 
.
.
, is equal and opposite to the weight, so 
.
.
on block Y:
