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

Therefore, the force on the object

Fairground ride:

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.

Car taking a turn on a circular path:

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.

Cyclotron:

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.

Windmill:

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:

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 m_p = 1.67*10^-27

Mass of the neutron m_n = 1.76*10^-27

Mass of the electron m_e = 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:

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

is an angular acceleration and r is a radius of the wheel.

The force acting on the passenger is a combined effect of the centripetal force and the force due to gravity. The mass of the passenger varies depending upon the centripetal acceleration and gravity.

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.

Read more on Is Gravitational Force A Contact Force: Why, How, When and Detailed Facts.

Frequently Asked Questions

Is central force a contact force?

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.

Also Read:

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• Negative electrostatic force
• Boiling point and molecular forces
• External forces examples
• Conservative force examples
• Is net force a vector
• Air resistance force examples
• Forced oscillations examples
• What increases the force of a magnetic field

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.

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

m_A 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.

Read more on 15+ Contact Force Examples: Exhaustive Insights And Facts.

Frequently Asked Questions

Is a muscular force a frictional force?

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.

Also Read:

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• Boiling point and molecular forces
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• How to find tension force with friction
• Is air resistance a force
• Non contact force examples
• Displacement and force
• How to find friction force without coefficient
• Muscular force examples

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

M_E is the mass of the Earth

M is a mass of the object

R_E 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 2^nd 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

Work done = mgh.

The work done is equal to the potential energy of an object at a certain height ‘h’ from the ground.

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.

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.

Read more on Is Magnetic Force A Contact Force: Why, How, When and Detailed Facts.

Frequently Asked Questions

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 M_E= 6*10²⁴

The mass of the Sun M_s= 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 M_s= 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.

Also Read:

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• Is gravity an external force
• Is net force a vector
• Magnetic field and force
• Natural frequency and forced vibrations
• Gravitational force formula
• Is tension a contact force
• How to find normal force on a horizontal surface
• How to find normal force with tension

In this article, we are going to discuss some magnetic force examples and understand its application in more detail.

Following is a list of some examples and applications of a magnetic force that we are often using and are basically working on the application of a magnetic force:

Examples of the Magnetic Force and Some Application

Magnetic force can be converted to another form such as mechanical to mechanical in attraction and repulsion; mechanical to electrical in generators, microphones; electrical to mechanical in motors, loudspeakers; mechanical to heat energy as eddy current, hysteresis torque devices, etc. and hence magnetic force has wide application in industries, factories, electronic devices, laboratories, etc. Let us discuss some examples of the magnetic force.

Two Bar Magnets

The bar magnet has two poles, one pole of the magnet carries more number of protons having a positive charge, thus making it positive, and another pole constitutes more number of electrons, hence negatively charged.

The positive pole of the magnet will tend to attract towards the negative pole of another magnet as the positive pole with more number of protons will tend to attract electrons from another pole of the magnet towards it and vice versa, thus both showing the forces of attraction towards each other.

Similarly, when two positive or negative poles are bought closer to one another, will show repulsion as the pole already having a majority of the protons will not accept more protons towards it, or a pole with the majority of the electrons will not pull more electrons towards it, hence the force of repulsion is seen by both the poles of the magnet.

This follows Newton’s Third Law, according to which “Every action has an equal and opposite reaction.”The magnitude of the force experienced by each of the poles during attraction or repulsion is always equal, and the force always acts in the opposite direction.

If the positive pole of the magnet is brought closer to the neutral object, then the electrons from the object will get attracted towards the positive charges thus gathering at one side of the object and repels the protons away from it leaving behind the protons on the other side. And thus, the protons and the electrons will get separated from the neutral object forming two different poles of the charged particles.

Current carrying wire

The above diagram represents the conductor of length “L” carrying a current “I” placed in the magnetic field. On application of current, the charges in the conductor will show some mobility and an effect so produced due to the presence of magnetic field is called electromagnetism. The force experienced on the unit length of the wire is given as

F=I(L*B)

If is an angle between the current-carrying wire and the direction of a magnetic field, then the magnitude of the force is

F=ILB\sinθ

This equation shows the relationship between current and a magnetic field.

Two parallel current-carrying wires

Consider two current-carrying wires placed parallel. The magnetic field produced by a current-carrying wire 1 at a distance r from it is given by

B=μ₀I₁/2πr

The force experienced due to the presence of the second current-carrying wire in parallel with the first carrying current I₂ is

F=I₂LB₁

F=μ₀I₁I₂L/2πr

The force per unit length

F/L=F=μ₀I₁I₂/2πr

The two wires will show some force of attraction when the current flowing in both the wires is in the same direction, likewise, both will repel away if the direction of current is in the opposite direction.

Some applications of the magnetic field

Compass

A compass is a device used to find the direction. It consists of a magnetic needle mounted on a small pin that always points towards the North Pole of the Earth. Since the Earth’s magnetic field is positioned in the North-South direction, the magnetic needle gets align itself in collaboration with the magnetic effect felt due to Earth’s magnetic field.

MRI Scanners

Magnetic Resonance Imaging machines are widely used in medical diagnoses. They produce large magnetic field strength and are used to take pictures of the human organs for detailed studies by passing the radio waves.

Electric Motors

A coil in a motor generates a magnetic field on the application of current. The magnetic field thus produces induces magnetic force with the magnet that causes motion or spinning of the motor. So basically, the magnetic force is utilized by the motor to create mechanical energy from electrical energy.

Speakers

Speaker, microphones are devices that come with an electromagnet that converts the electric signal into audible sound. The electromagnet is like a coil, when current flows through this coil it produces a magnetic field. This coil frequently attracts and repels from the magnet to produce an audio effect.

Refrigerators

Refrigerators have a magnet embedded in their door made up of weak ferromagnetic ceramics like barium ferrite or strontium ferrite. Due to this, the refrigerator door always apt to close itself whenever the refrigerator is opened.

Microwave

Ovens have a magnetron which is a vacuum tube designed to generate or amplify the microwaves by controlling the flow of an electron by applying an external magnetic field. A magnet is placed around this vacuum tube that provides magnetic force and causes the electrons to move in a loop. Thus generating heat and cooking food.

Cars

The car uses electromagnetic property inside the engine for its motion. A magnetic coil is attached to an axle. By turning this magnetic coil, the wheels are also made to turn, thus controlling the steering of the car.

Fans

The magnets in the rotor of a fan are repelled by the stators which increase the movement of the rotor. The electric current switches one of the sets of the magnet and hence, the rotor and stator repel themselves away from each other every cycle of the rotor. This is achieved by the application of the magnetic force.

Magnetic Force

Magnetic force is one among the four fundamental forces. The magnetic force acts perpendicular to the motion of the particles, thus opposing the motion of the charges; hence the charged particles tend to deflect due to the magnetic force. 

The magnetic force depends upon the charge and the velocity of the particle in a magnetic field and the external field applied to the conductor and is given by F=qvB. In presence of the external field, the electrons and protons align themselves according to the field applied. The magnetic field density depends upon the density of a magnetic flux crossing per unit cross-sectional area of the material.

Types of magnetic force

1) Attractive Force: When two poles of unlike charges are bought near, both the poles tend to attract towards each other. The force exerted by the poles on each other is known as an attractive force.

2) Repulsive Force: When the two poles of like charges are bought near, the poles repel away from each other. The force felt on each of the poles is known as a repulsive force.

Theory and the Classification of Magnetic Materials

According to the Pauli Exclusion Principle, “No two electrons will have the same quantum number. No more than two electrons can occupy the same orbital. Electrons present in the same orbital must have opposite or anti-parallel spin.”

The electrons pair up with the electrons having an opposite spin and canceling out the magnetic moment produced by each other. Well, the unpaired electron shows the spin and orbital movement of the atom and gives the direction of the magnetic field.

Based on the number of free electrons available, various materials show different magnetic characteristics. If the number of available unpaired electrons is greater, then, the magnetic effects seen in the material will also escalate. The materials are classified as follows:-

Diamagnetic: Diamagnetic materials show the force of repulsion on both the poles of a magnet. These materials tend to oppose the magnetic flux through them and hence are repelled by the magnetic force. Examples: Carbon, Gold, Silver, water, etc.

Paramagnetic: Paramagnetic materials show properties of magnetization only when a strong magnetic force is applied to them. They are weakly attracted to either of the poles of a magnet. Examples: Oxygen, Aluminum, brass, etc.

Ferromagnetic: Ferromagnetic materials are highly magnetized materials. They have many unpaired electrons which are aligned forming colonies of charges and hence becoming highly attractive. They can retain their magnetization and even become a magnet. Examples: Iron, Nickel, Cobalt, etc.

On what factors does the magnetic force depend

The magnetic force basically depends upon the magnitude of the charge, the velocity of a charged particle, and the external magnetic force. In the electromagnetic region, this force is described as Lorentz force and is represented as:

F=q(E+v*B)

Force due to the magnetic field is given as

F=qvB

The magnitude of the magnetic force

F=qvB sin θ

Where θ varies from 0 to 180⁰ and <180⁰.

The direction of the force is found out using Fleming’s Right-Hand Rule and Right-Hand Grip Rule as shown below,

Right Hand Grip Rule

The right hand is imagined as the current carrying conductor. The direction of the current is symbolized by the thumb and the field lines are running around the conductor forming concentric circles as seen in the figure.

Fleming’s Right-Hand Rule

In Fleming’s Right-Hand Rule, the thumb shows the direction of force, while the index and middle finger indicate the direction of magnetic field and electric current respectively.

For a current carrying conductor placed in a magnetic field, the force experienced on a unit cross-section length of the wire is given as

F=qvB sin θ

because, velocity = distance/time

Hence, we can rewrite the above equation as:

F=a/LTBsin θ

Current is defined as a charge per unit time and given by I=q/t

Therefore, F=BILsin θ

Read more on “What Objects Have Magnetic Force: Exhaustive Facts On Various Objects“.

Frequently Asked Questions

What force is a magnetic force?

The magnetic force depends upon the majority of the charge carriers, the direction of a field and the current.

The magnetic force is basically the force of attraction and repulsion between the positive and the negatively charged particles.

Consider a wire placed between the two poles of the magnet. If the current flowing in a wire is 15A, find the magnitude and the direction of the force experienced on 10 mm length of the same wire if the magnetic field is 0.2T.

A magnetic field is perpendicular to the direction of the current flowing in the wire, therefore

sin θ=1

The force experienced on a 10mm section of the wire is

F=BIL=0.2T*15A*0.01m=0.01N

If the magnetic field lines are running towards North and the acceleration of the electrons is perpendicular to the direction of the field, then the force is exerted outward.

What material is used to make a horseshoe magnet?

A horseshoe magnet is a U-shaped magnet and both the poles are in the same direction that helps to create a strong magnetic field.

It is made up of AlNiCo an alloy of Iron and an iron bar is attached to the two poles of the magnet to prevent demagnetization. This was previously used in microwave ovens in the magnetron tube.

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In this article, we are going to study what objects have magnetic force and possess a force relevant to the field.

The two objects with a motion of charges in the same direction experience a magnetic force of attraction, whereas, the objects with charges moving in the opposite direction show repulsive force between them.

What is a Magnetic Force?

A magnetic field is produced when a conductor is placed in the electric field; an electromagnetic force is induced in the conductor due to the motion of the unpaired electrons.

The force experienced by the particle in the field opposing their motion is a magnetic force. A magnetic force may be attractive or repulsive based on the alignment of the magnetic dipoles inside the material.

Types of the Magnetic Force

Attractive Force: When the two objects having the dipoles arranged in the same direction tend to attract towards each other, the force experienced by the objects on each other is known as an attractive force.

Repulsive Force: Two objects having the dipoles arranged in the opposite direction tends to repel from each other, the force exerted by the objects on each other is called repulsive force.

Do all objects have a magnetic force

The electrons pair with the opposite spin, which results in the cancellation of the magnetic field produced by each of the electrons. When the magnetic field is set up in the material, positive and negative carriers inside the material become mobile and arrange according to the external field exerted.

If the number of electrons available is greater, then, the magnetic effects seen in the material will also escalate. Based on these, the materials are classified as follows:

Diamagnetic: Materials that have no unpaired electrons shows diamagnetism, these material tends to oppose the magnetic flux through a unit cross-sectional area and are hence repelled by the magnetic force. Examples: Gold, Copper, Silver, H₂O.

Paramagnetic: Material has an unpaired electron, and these unpaired electrons tend to align themselves in the direction of the applied external field, hence showing magnetic behavior in presence of the external field. Examples: Aluminum, Di-Oxygen, Lithium.

Ferromagnetic: Material is strongly magnetized in presence of the magnetic field and retains its magnetic property even in absence of the external magnetic field.  Examples: Iron, Nickel, Cobalt.

Read more on What Produces the Strength of a Magnetic Field.

What objects use magnetic force

The application of the magnetic force is widely used due to its attractive and repulsive behavior.

Devices like electric motors, door latches, speakers, data storage devices, refrigerators, compass, clinometers, microwaves, cars, etc. use a magnet.

Let us discuss some examples below to get an idea of the commonly used objects in our day-to-day life and whether these objects show magnetic behavior or not.

Is a paper magnetic

No. Paper is a bad conductor of heat and electricity as it is made up of carbon. A carbon atom has atomic no. 6 having 4 electrons in its outermost shell, which is a half-filled electronic configuration of an atom and the most stable state of the atom. The spin of all six electrons cancels the magnetic moment produced by each thus making the total magnetic moment zero. Hence, carbon shows no magnetic behavior.

Is glass magnetic

Glass is manufactured using Silicon Dioxide, Calcium Carbonate, and sodium carbonate. Silicon is a semiconductor, that is, it partly behaves as a conductor and partly as an insulator. It is a dielectric and can transmit electric force without conducting.

When the external field is very strong, the dipoles of the silicon glass may align in the direction of the fields. Glass has very low permeability and hence shows diamagnetic characteristics, but the percentage of composition of these elements is very negligible to make the glass magnetic. Some glasses are also made up of cobalt which shows magnetic behavior.

Is an iron nail magnetic

Yes, an iron nail is magnetic. The atomic number of Iron [Fe] is Z=26. The electronic configuration of this element is given by [Ar]3d⁶4s². The valence electron of Feis 8 and has 4 unpaired electrons. Hence, iron shows ferromagnetism and retains its magnetic property even in the absence of an external field.

Is a wood magnetic

Wood is an insulator. It is a bad conductor of heat and electricity, and hence no field is induced inside the wood and no field of attraction appears.

Is gold magnetic

Pure gold is not magnetic but shows magnetic behavior in presence of an external field. The electronic configuration of Ag: [Xe] 4f¹⁴5d¹⁰6s¹. The 6s orbital has one unpaired electron which is a half-filled shell. Because of this unpaired electron, gold shows diamagnetic behavior in presence of the external field. Moreover, the magnetism of alloy of gold depends upon which metal is used to make an alloy with gold.

Is brass magnetic

Under normal circumstances, brass is not magnetic at all. It’s only when the strong magnetic field is applied to the brass metal, the electric current is set up inside the metal. This follows Lenz’s Law. When an electric current is set up inside the metal, it will show some interaction with the magnet.

Brass is an alloy of Copper [Cu] and Zinc[Zn] and shows a slight diamagnetic effect in presence of an external field, but it is very small to be noticed.

Is silver magnetic

The atomic number of silver [Ag] is 47 and the electronic configuration of Ag is [Kr]4d¹⁰5s¹. It has a half-filled, stable 5s orbital with one unpaired electron. Silver is not magnetic but will show some interaction with a strong magnet under the influence of Lenz Law which states that the current induced in the circuit due to the motion of the charged particles is directed to oppose the change in flux and hence exerts a force opposing the velocity of the particles.

The magnetic moments induced will produce an eddy current within the silver metal. This eddy current is responsible for the interaction of the metal with magnet. Hence, silver shows diamagnetism in presence of an intense magnetic field.

Are whiteboards magnetic

Whiteboards are not magnetic. Whiteboard mostly has steel sheets that provided magnetism across the surface of the board. Steel is an alloy of iron that has ferromagnetic characteristics.

What metal is magnetic

Magnetic materials are attracted towards the magnet and may even become magnetized. The ferromagnetic metals will definitely show magnetic effects naturally because they are magnetized. Even, the metals made from the alloys of the ferromagnetic material will show magnetic behavior. 

Is a chalkboard magnetic

Chalkboards are not magnetic but can be made magnetic using galvanized steel and by applying magnetic primer.

Is a penny magnetic

No. Penny is a coin made up of Bronze, an alloy of 95% copper and 5% Tin and Zinc. This alloy does not show any magnetic behavior.

Is plastic attracted to magnets

No. Polyethylene is the most commonly used plastic nowadays. Plastic is a bad conductor of heat and electricity, known as an insulator; hence does not consist of magnetic properties.

Is nickel magnetic

Yes. Nickel has atomic number 28. The electronic configuration of nickel is [Ar] 4s², 3d⁸ and has two unpaired electrons. Hence, it shows ferromagnetic characteristics.

Can trees be magnetic

No. Wood is a bad conductor of heat and electricity. But, the tree has certain elements that may show magnetic characteristics.

Are Diamonds magnetic

No, because diamonds are made up of carbon which has 6 electrons, and all the electrons pair up with each other which cancels out the magnetic moment produced due to the spin of the electrons. Hence, the total magnetic moment by the carbon atom is nil and does not show any magnetic behavior. But some synthetic diamonds are magnetic because of some inclusions during their manufacturing.

Is Black Sand magnetic

Black sand is formed due to a result of the volcanic eruption. The molten magma is often comprised of Fe-rich lava. The mineral usually found in the area of volcanic eruption with more concentration of iron is magnetite. Magnetite being rich in Fe-concentration is ferromagnetic and hence the black sand is magnetic.

Is an aluminum can magnetic

Aluminum has atomic number 13. Its electronic configuration is 1s²2s²2p⁶3s²3p¹. Since Al has only one unpaired electron the paramagnetism is expected, but aluminum is not magnetic under normal conditions. Only when it is introduced in the magnetic field region, small eddy currents are established inside the Al-metal which instigate magnetic dipoles and hence shows paramagnetism.

Is a lead solder magnetic

Lead with atomic no.82, [Xe] 4f14, 5d10, 6s2, 6p2; is not magnetic; but shows weak diamagnetism in presence of external magnetic field as it acquires magnetism in the direction opposite to the field.

Is there magnets in dirt

Yes. When we left the magnet in the open air, we will notice that the magnet will gather some dirt on it. Dirt gets magnetized only when we apply the magnetic field to it.

Is Sugar magnetic

The chemical formula of sugar is C₁₂H₂₂O₁₁. It interacts in electromagnetic fields and thus can be affected by a magnetic field, but is not magnetic.

Is Salt attracted to a magnet

Rock salt shows very weak magnetism as it contains few paramagnetic or ferromagnetic minerals. Salt of cobalt shows very high magnetic behavior. NaCl is diamagnetic; all spins are paired in Na+ and Cl- ions.

Can magnets move water

Water is slightly repelled by a strong magnet. Water has 2 hydrogens and one oxygen atom, when both combine to form water, there are no free electrons left behind to attract anything towards it to pair, hence water is diamagnetic.

Read more on objects that produce a magnetic field.

Frequently Asked Questions

Does a magnet transform one form of energy to another?

A magnet transfers one form of energy into another without any loss of its energy.

Such as mechanical to mechanical in attraction and repulsion; mechanical to electrical in generators, microphones; electrical to mechanical in motors, loudspeakers; mechanical to heat energy as eddy current, hysteresis torque devices.

How a magnet affects the growth of the plant?

It is noticed that the plant grows faster when it is surrounded by a magnet on the soil.

A magnet attracts ferromagnetic elements from the soil towards it, which becomes easier for the roots of the plant to intake these elements and grow at a faster rate.

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