I am Prajakta Gharat. I have completed Post Graduation in physics in 2020. Currently I am working as a Subject Matter Expert in Physics for Lambdageeks. I try to explain Physics subject easily understandable in simple way.
When a system of particles is isolated from the rest of the world, the total momentum of the system is conserved. In this article, we will see how is momentum conserved in an isolated system.
The conservation of momentum law is derived from the second and third laws of motion, respectively. The overall momentum of the system has always been conserved in an isolated system. The forces in nature are internal to the system and add up to zero for the entire system. Because the external force on the system is zero, the system’s momentum is conserved.
We will discuss the following points in this article:
Momentum may be defined as the quantity of motion experienced by a body under consideration. The momentum of a body is defined mathematically as a function of its mass and the velocity at which it is traveling, respectively. Generally, the isolated system isn’t very precise, but it usually covers the bodies that are being looked at.
Conserved does not always imply constant. It expresses the fact that something cannot be produced or destroyed at any moment. The condition in which a system is exposed to an external force net force, the momentum of the system changes, but it is conserved. Hence, everything about it is conserved at all times, in all situations.
Why is momentum conserved in an isolated system?
In this case, when there is no force from outside of the body system, the system is referred to as an isolated system.
According to Newton’s second law of motion, because no external force occurs on the system, The change in momentum is equal to zero; hence, the linear momentum is conserved.
dP/dt = 0
Henceforth, |P|= constant, (as derivative of a constant function is 0)
(In which P=mv=linear momentum is used)
The entire linear momentum of an isolated system, that is, a system that is not subjected to any external forces, is conserved.
Ans: For the sake of simplicity, Linear Momentum is used to grasp the quantitative idea of motion.
The linear momentum is a measure of motion that quantifies both velocity and mass. It is defined mathematically as the product of mass and velocity.
It is represented as follow
P = mv
Where, P = Linear momentum
m= mass and v = velocity
Q. What is angular momentum?
Ans: In simple words, it is the momentum of rotating objects.
The term “momentum” refers to the product of the object’s mass and its velocity. Momentum may be found in any object that is moving with mass. The main difference between angular momentum is that it deals with revolving or spinning things.
It is represented as follow
L = mvr
Where, L = Angular momentum
m= mass, v= velocity and r = radius
Q.What do you imply when you speak of conservation of momentum?
Ans: Conservation means no change in the system or one can say that the initial or final value remains the same. The conservation of momentum law could be stated as follow:
“For two or more bodies in an isolated system acting upon each other, their total momentum remains constant unless an external force is applied. Therefore, momentum can neither be created nor destroyed.”
Q. What is the formula of law of conservation of momentum and what are examples of it?
Ans: The law of conservation of momentum can be represented as follow:
Where,
The masses of the bodies are denoted by m1 and m2, and the initial velocities of the bodies are denoted by u1 and u2. The final velocities of the bodies are represented by v1 and v2.
With the help of Newton’s cradle, you can see how the balls in a row of balls will push forward when one ball is raised and then let go of the ball at the other end of the row.
Q. In the background, there are automobiles with weight of 5 kilogrammes and 6 kilogrammes, respectively. An automobile with a mass of 5 kg is moving at a velocity of 4 m.s-1 in the direction of the east. Calculate the velocity of an automobile with a mass of 6 kg in relation to the ground.
Q. Sedans of 100 kg and 200 kg mass are at rest. A 200 kilogramme car travelling at 60 m.s-1towards the west. Find the car’s velocity relative to the land.
Ans: Given,
m1 = 100 kg, m2 = 200 kg, v2 = 60 m.s-1, v1 = ?
When we look at the law of momentum, we can see that it holds true that,
Pinitial = 0, as the sedans are at rest
Pfinal = p1 + p2
Pfinal = m1.v1 + m2.v2
= (100 kg). v1 + (200 kg). (60 m.s-1)
Pi = Pf
0=(100 kg). v1 + 12000 kg.m.s-1
v1 = 120 m.s-1
Therefore, the sedan car velocity relative to the ground is 120 m.s-1
Q. What is the meaning of an isolated system?
Ans: There must be two or more objects in order for a system to exist. For example, a system that is completely isolated from external influences is referred to as an isolated system.
A system that is isolated is one in which the only forces that contribute to the change in momentum of an individual item are the forces operating between the components themselves, and hence the object is not affected by any external forces.
There are two things that must happen for there to be a net external force:
There is an external force present in the system that originates from a source other than the two objects of the system.
A force that is unbalanced in relation to other forces.
On a broad level, Energy is a quality of objects that may be transferred to other objects or transformed into different forms, but it cannot be created or destroyed. In objects, it is a quality that may be transmitted from one item to another or turned into multiple forms in different situations.
Kinetic energy is defined as the energy that is associated with items that are in motion or moving. For example, while an aeroplane is in flight, the aeroplane is moving through the air at a high rate, exerting force on its surroundings and causing change to occur. The jet engines work by transforming potential energy in the fuel to kinetic energy in the form of movement and thrust.
Our understanding of KE and how we apply it in science is well-established. Make it more relatable now by talking about the five distinct types of KE and how we utilise them in our everyday lives, to illustrate our point.
It is the form of energy that can be seen with our eyes that is known as mechanical energy. The greater the speed at which an item travels and the bigger the mass it possesses, the greater the mechanical energy it possesses and the greater the ability of the thing to perform work. A good illustration is when a bowling ball hits a pin in a game of bowling. A windmill, on the other hand, can collect wind energy, and a hydroelectric dam can create power from a moving water source, which is more significant.
Electrical energy is the amount of energy that electrons have when they are travelling. A small group of particles known as atoms make up all of the items in the universe. Atoms are composed of very small components such as electrons, protons, and neutrons, which combine to form a molecule.
In an atom, the electrons that are present travel around the nucleus of the atom at all times. Atomic electrons gain energy and become free when a voltage or electric field is delivered externally to the atom’s nucleus. Electrical energy or electricity is the term we use to describe the energy carried by a free electron. A desk light or a cell phone that is connected into the wall are both powered by the movement of these electrons in our daily lives.
Radiant energy is the term used to describe the energy involved in electromagnetic radiation or light. Radiant energy is also referred to as electromagnetic energy in some circles. This energy has the ability to move through space or via a medium. As we all know, kinetic energy is defined as the energy of motion. Radiant energy is constantly in motion as it travels across space or via a medium. This has resulted in it being referred to as a kind of kinetic energy. Radiant energy is emitted by everything that has a thermal state.
A number of various types of radiation can be used to represent radiant energy, including gamma rays, X-rays, ultraviolet light, visible light (violet, indigo, blue, green, yellow, orange, and red), infrared radiation, microwaves, and radio waves. Radiant energy is also used to describe the energy that the sun sends out into space to reach the planet. If the energy is directed in a straight path, it moves at an extremely high speed (3 × 108 m/s).
Depending on the wavelength of the radiant energy or light energy, it may be visible to the human eye or invisible to the naked eye. The joule is the SI unit of radiant energy, just as it is for all other forms of energy in the universe. The sun’s heat is a clear example of radiant energy. Lightbulbs, a toaster in your kitchen, and X-rays are more examples.
Heating and cooling are both examples of thermal energy, which may be perceived by people in the form of heat. Thermal energy, on the other hand, has everything to do with the amount of atom and molecule activity in a given item. The faster the speed at which they are travelling, the greater the probability that they will collide with one another. In a physical object, thermal energy refers to the internal energy produced by the motion and collision of atoms and molecules. The temperature or a thermal energy of a substance can be measured in degrees Celsius. Thermal energy is indeed referred to as heat energy in some circles.
It is the atoms and molecules that serve as the fundamental building blocks of all stuff in the cosmos. Throughout this system, all of the atoms and molecules are constantly moving. We can’t observe the movement of this energy with our eyes since it is invisible to them. When it comes into contact with our skin, we can feel it. For example, when standing outside in the sun, you cannot see the heat. But you can always feel the heat.
Thermal energy is created when atoms and molecules clash with one another as they move faster than they can go. The kinetic energy of the atoms and molecules in a substance’s composition determines the thermal energy of the thing. The atoms in hotter substances will travel or vibrate more quickly, resulting in a greater amount of kinetic energy. As a result, they will generate more thermal energy.
The kinetic energy of the atoms in colder substances, on the other hand, is significantly smaller. As a consequence, they will produce far less heat. Thermal energy, like all other types of energy, is measured in Joules as well as other units of measurement like Celsius. Examples of thermal energy include the heat generated by your oven and the energy required to power your car’s engine. Another example includes the word “thermal” in its name: geothermal energy is a renewable resource that we use to create electricity for usage in our homes and businesses.
An example of thermal energy of the sun and the earth (Geothermal)
Vibration of an item generates sound energy, which is a sort of energy. By transferring energy between particles, this energy may travel across any material and can be detected by the human ear when it gets close enough to the ears. If you have a vibrating object in your environment, the energy from the object is transmitted to the nearby surrounding particles, enabling them to vibrate as well. Following that, the particles smash with another set of particles, and the cycle continues. Sound energy is transferred from one particle to another in the same way.
Vacuum does not permit the transmission of sound energy since it does not contain any particles that may serve as carriers of sound energy. It can only be transported through some kind of medium such as water, air, or solid. Sound is produced by vibrations, which may be produced by anything from the loudest drum to the smallest buzzing bee. Alarms, car horns, thunder storms, conversing with others, drumming, crackers, and other forms of sound energy are examples of this type of energy.
So, these all are the important five types of kinetic energy
Frequently Asked Questions (FAQ)
Q. When it comes to kinetic energy, what is the definition?
Ans: Basically, there are two types of energy. One of these is kinetic energy (KE).
It’s the amount of effort necessary to accelerate a body of a given mass from rest to a certain velocity.
Q. What is the formula for kinetic energy or how do we represent the kinetic energy?
Ans: The equation of kinetic energy is shown as below:
Where,
KE = Kinetic energy
m= mass of the body
v= velocity of the body
Q. When an object with mass of 100 kg is moving with the velocity of 20 m/s. Then what will be its kinetic energy?
Ans: We know that the equation of kinetic energy is given as
KE = ½ mv2
Given, m = 100 kg and v = 20 m/s
Putting these values in above equation of kinetic energy, we get
KE= ½ (100 kg) × (20 m/s)
KE = 1000 J or 1 KJ
Therefore, the kinetic energy of an moving object is 1000 J or 1 KJ.
Q. Describe how the kinetic energy differs in nature from the potential energy.
Ans:Potential energy refers to the energy that a body has just because of where it is in relation to other objects. Kinetic energy refers to the energy held by a body as a result of its movement.
Q. When it comes to Kinetic Energy, what are its characteristics?
Ans: Kinetic energy is created when a body moves. It permits us to shift speed. Here are some more kinetic energy characteristics:
When the object’s velocity changes, kinetic energy may rise or fall depending on that change.
It is more prominent in heavier items.
It has the ability to convert into different forms of energy.
Any moving item will experience this phenomenon regardless of its direction of movement.
Its units of measurement are joules (J).
Q. What are the different examples of kinetic energy?
Ans: Following are the different examples of the kinetic energy:
In a sense, light energy is kinetic energy that may cause different types of light to be visible to human eyes. Let us see some of the light energy examples in our surroundings.
When you hear the word light, the first thing that comes to mind is the sun’s light! The most obvious light energy example is sunlight. It is a renewable and natural source of light energy that is found in nature. It is this that motivates you to get up early in the morning by providing you with a sensation of warmth and brightness.
Laser light:
An acronym for LASER is Light Amplification by Stimulated Emission of Radiation. A laser is a very uncommon type of light source and a laser is a device that produces a beam of extremely strong light. When compared to the light created by conventional white light sources (such as a light bulb), laser light has several significant advantages, the most important of which are monochromatic, directed, and coherent. Lasers emit an extremely narrow beam of light when they are turned on. The term “monochromatic” refers to the fact that all of the light emitted by the laser has a single wavelength.
Lightbulbs are used to provide illumination in a room:
Electric current warms a tungsten filament, which produces light. Incandescence refers to the emission of light that occurs as a result of something being heated. Depending on the bulb shape and filament type, they can provide the light that is equally distributed throughout the bulb.
Traffic light:
This type of signaling equipment, which is sometimes referred to as traffic lights or traffic signals, is strategically positioned at road intersections, pedestrian crossings, and other locations in order to manage traffic flow and avoid accidents. These are basically the incandescent source of light energy. Nowadays, traditional incandescent traffic lights are being replaced with LED traffic signals, which have begun to mimic their appearance.
Hot objects:
Other than the sun, we have tube lights and bulbs as sources of light. The filament, which is usually tungsten (because of its high melting point and resistance), heats up as electricity passes through it. The filament glows as it heats up. This is why metals turn red hot. Also, you can see these hot objects light emission in your kitchen while cooking food in utensils like frying pans and cooking pots kept on gas burners.
Thermal radiation causes materials to glow when heated, and this is due to the nature of the material. When heated, atoms and subatomic particles begin to vibrate, indicating that matter is composed of these particles. In accordance with certain thermodynamic laws, electrons vibrate and oscillate between higher and lower energies. This causes the substance to glow as a result of the interaction. When we heat a thing, we are supplying it with energy, and the heated object emits a portion of this energy in the form of visible light. After all, light is considered to be a kind of energy.
Fireworks:
Firework basically works on the principle of excitation and deexcitation phenomenon. Fireworks are created from a variety of chemical compounds that contain metals. When heated, these compounds emit different colors of light depending on the chemical. When the electrons in a metal return to their ground state, they will emit shorter wavelengths of light (such as blue light) as a result of the higher energy they have absorbed. However, the electrons in metals that absorb lower energy return to their ground state, they will emit longer wavelengths of light (such as red light) as a result of this. A large number of fireworks colors are derived from different types of metal salts.
We all have seen glow worm in our life which is the most beautiful and fascinating light energy example from nature. The bioluminescence of glow worm larvae is similar to that of other insect larvae. It is a live organism’s ability to produce light. To create chemical energy, the enzyme called luciferase combines with the waste product luciferin, the adenosine triphosphate molecule also known as ATP, and oxygen in the presence of the enzyme. The blue/green light generated by this chemical energy is visible to human eyes.
It is via this process that these creatures are able to warn predators that they are not worth attacking because of the poisons inherent inside their bodies. It also aids them in attracting other insects in order to feast on them. In addition, they use it to communicate with one another.
Bioluminescence, on the other hand, is present in practically every sort of species found in the deep water, including squids, octopuses, fishes, shrimps, single-celled animals, and jellies of all types. These all are light energy examples from the ocean ecosystem. The generation of light by a chemical reaction occurring within a living species is known as bioluminescence. The light is caused by the reaction of a chemical known as luciferin with oxygen. As a result, energy is released and light is emitted into the environment.
There are millions of objects in our universe which emit light and are light energy examples. For instance, we can consider here Andromeda galaxy as a light energy example because it can be seen with an unaided eye. The Andromeda galaxy is a cluster of a trillion stars that is located 2.5 million light-years away from Earth. It is sometimes referred to as M31 since it is the galaxy that is closest to the Milky Way. Also, apart from this, there are different stars, pulsars, quasars, comets, nebulas which are the light source examples.
We all utilize various sorts of LED torches for a variety of functions throughout our daily lives. These torches generate light energy from the batteries that are included within the torches themselves. If our batteries go down, we can easily replace them and we will have access to light energy once more for our purposes.
So herein we have seen various light energy examples in our surroundings and our day to day life.
Q. What is the process through which light energy is created?
Ans: Photons, the smallest units of energy that make up light, are the building blocks of visible light. Photons are generated by the movement of atoms during the heating process of an item. Photons are created in greater abundance in hotter objects.
Q. How does the light travels?
Ans: Light energy moves in waves, which are made up of photons. Light energy moves extremely quickly — in fact, nothing travels faster than light.
Q. What are the uses of light energy?
Ans: Light energy is utilized to assist humans in seeing — whether it comes from natural sources such as the Sun or fire, or from manufactured sources such as candles or lightbulbs.
Intensity: Depending on how quickly light energy is released by the source, the amount of light energy emitted by the source influences the intensity of the light emitted by the source. As another definition, it may be defined as the brightness measured as the rate at which light is emitted from a unit surface or as the amount of energy emitted per unit time per unit area in a given amount of time. Watts are the units of measurement for electrical power.
Frequency: The number of crests that pass across a specific point in a second is defined as the frequency of light.
Wavelength: In general, the length of a wave is defined as the distance between two successive crests or troughs of the wave. A vacuum has the same speed as air, hence light waves move at the same speed through a vacuum. The wavelength and frequency of light have an inverse connection, with the higher the frequency resulting in a shorter wavelength.
Polarization: When unpolarized light is converted to polarised light, this is known as polarisation. Unpolarized light is defined as light waves that vibrate in more than one plane at the same time.
Phase: Within a cyclic waveform, phase refers to a certain moment in time during the time period. When the waves are in phase with one another, the intensity of light rises.
Visible light: Light is the only type of electromagnetic radiation that can be seen with the naked eye, or in other words, without the use of a microscope, telescope, or other special equipment. In spite of this, sunlight is by far the most prevalent source of energy, visible light, it may also be emitted by light bulbs, lanterns, flashlights, and other gadgets, among other things.
Infrared light: Infrared radiation is also a form of electromagnetic energy that releases heat and may be detected. It is utilized to turn on your television using the remote control since infrared rays may flow from the remote control to the television set.
X-ray and ultraviolet (UV) light: X-rays and ultraviolet light are brief light waves that are used by doctors to picture the inside of the human body in order to determine what is wrong with the patient. X-rays are frequently used by dentists to determine the extent of tooth decay.
Kinetic energy is the quantity of energy that an item has as a result of its motion. Herein we will see motion energy examples in our surroundings as listed below:
Now, let us see these motion energy examples in details as follow:
Motion energy examples
An airplane flying in the sky
For the reason that it has huge mass as well as a high velocity, a flying aeroplane has a significant quantity of kinetic energy to propel it forward in the air. When an aeroplane is in flight, the kinetic energy of the aircraft is increased by both of these factors. In fact, it is because of this that planes are able to fly at such high altitudes.
A moving car
Cars in motion contain a certain amount of kinetic energy. This is due to the fact that they have a certain amount of mass and velocity. As a result of using the kinetic energy formula, we now understand that when we compare the kinetic energy of two vehicles travelling at the same velocity on a road, we will arrive to the conclusion that the truck has more kinetic energy than the car because of its bigger size.
Consequently, because the amount of kinetic energy contained in an item moving increases as its mass increases, a truck will have far more than a vehicle.
Power facilities that generate electricity via the use of water are referred to as hydroelectric power plants. When the running water, which contains some kinetic energy, strikes the turbine installed in the dam, the kinetic energy of the water is turned into mechanical energy, which is then used to power the dam. This mechanical energy drives the turbines, which in turn results in the generation of electrical energy at the end of the process.
Despite the fact that this example does not serve as a practical demonstration of kinetic energy on a daily basis, it is a really intriguing occurrence that occurs in the solar system. The fact that meteoroids are dispersed over our solar system is something you may already be aware of. When a meteoroid arrives close enough to the earth’s atmosphere to be drawn by gravity, it is said to be “attracted.”
As a result, it begins to descend freely from the sky at a high rate of velocity. Because of the meteorite’s immense size and weight, the kinetic energy of the meteorite is extremely high at the time of its impact. An explosion occurs when a meteor impacts the surface of the earth with such a significant quantity of kinetic energy as it does. As previously stated, this is also the reason for the appearance of meteoroids on the surface of the earth’s atmosphere.
The potential energy of a bus at the top of a hill is greater than the kinetic energy of the bus because of the height, with nearly negligible coefficient of kinetic energy. As the bus accelerates down the hill, the potential energy owing to the height decreases, and the kinetic energy increases as the vehicle accelerates down the hill.
After a while, the value of both kinetic and potential energy will become equal, and this will be the case. kinetic energy will be at its maximum when the bus reaches the bottom of the hill, and potential energy will be at zero as long as it maintains a steady speed during the trip.
Glass dropping on the floor
What happens when we drop a glass on the floor by accident? At first, it just has potential energy at its greatest point, but as gravity takes over and the speed increases, the mass of the glass and its velocity take over as the driving forces behind the slow growth in kinetic energy. When the glass is at its lowest position, just as it is about to touch the ground, the kinetic energy is at its peak, but the potential energy is at its lowest point or is negligible. Finally, when the glass shatters against the ground and the kinetic energy is released, the process is completed.
Skateboard
When a person on a skateboard comes to a complete stop, the kinetic energy of the skateboarder will be zero, just as it is in the case of a bicycle. kinetic energy of the skateboard constantly grows in value as the skateboard is propelled forward. The weight of a skateboard rider, when paired with the rapid speed of the board, results in a significant quantity of kinetic energy being created.
Roller coaster
Roller coasters are entertaining to ride, but have you ever given any thought to what can happen to your carriage during a free fall? For example, when the roller coaster’s carriage reaches the top of the track, it has zero kinetic energy since the carriage is at rest.
However, when the carriage is allowed to fall freely, along with the steady rise in the speed of the carriage, there is also a gradual increase in the kinetic energy of the vehicle. Because of the increased mass and kinetic energy created by a greater number of passengers on a carriage while the speed is maintained at a constant rate, the carriage will accelerate faster.
Cycling
The kinetic energy of the moving bicycles is present. We turn our body’s energy into mechanical form by starting to pedal. This mechanical form is originally potential energy, which is eventually changed into kinetic energy owing to the action of the wheels, which is the mechanism behind it. Increased velocity results in an increase in the quantity of kinetic energy available. In order to bring the bicycle to a complete stop, we must apply the brakes in the opposite direction as the force in order to decelerate the bike and return it to zero energy.
Walking and running
When we walk or run, we generate kinetic energy, which is used to propel us forward. This explains why we feel quite warm when jogging or after walking for a long period of time. Sweating is created as a result of the heat generated by our bodies while we are jogging. A conversion of chemical energy into kinetic energy occurs when you walk or run, and this is referred to as kinetic energy transfer.
These all are the day to day life motion energy examples.
Frequently Asked Questions (FAQs):
Q. What do you mean by kinetic energy?
Ans: Moving object is said to have a kinetic energy.
The kinetic energy of an item is a measure of the work it can produce as a result of its motion.
Let us see what are the meanings of above listed energies
Radiant energy: Energy that is constantly in motion and travelling through a medium or space is referred to as radiant energy.
Thermal energy: A thermal energy, also known as heat energy, is formed when atoms collide with one another. This energy is produced as a result of the motion of the atoms when they interact.
Sound energy: The vibrating of an item results in the production of sound energy. However, sound energy cannot move in an empty space because there are no particles to function as a medium in a vacuum.
Mechanical energy: It is known as mechanical energy, which is made up of the total of kinetic and potential energy. Mechanical energy cannot be generated or destroyed, but it may be transferred from one form to another.
Q. When the speed drops, what happens to the kinetic energy?
Ans: Decrease in the speed slow downs the object.
The conversion of kinetic energy into other types of energy occurs whenever the speed of a moving item decreases. Potential energy, thermal energy, and other forms of energy are examples of such conversions.
Moving items contain energy, which is referred to as motion energy or mechanical energy. This energy is held in objects that are continually moving. As the object moves faster, the quantity of energy stored rises proportionally.
An object’s motion energy is the total of its potential and kinetic energy when it is put to use to do work.
Q. What do you mean by work?
Ans: When you open a door, you are doing ‘work’ on it (open)
When a force acts on an object, it is said to be doing work if the object moves, changes shape or position, or performs a physical activity as a result of the force’s action.
When an object moves, its motion energy is the sum of its potential and kinetic energy.
Kinetic energy refers to the energy that causes anything to move. In this article, we’ll go through everything in depth concerning what is the kinetic energy of light. Herein we will explore and find out the answers to the list of following questions:
Energy is a property of items that can be transmitted to other objects or changed into various forms, but it cannot be generated or destroyed. It’s a quality of entities that may be transmitted to other objects or transformed into other kinds. Kinetic energy is the energy associated with moving things or movement.
Light energy is a kind of electromagnetic radiation with wavelengths that the human eye can perceive.
Kinetic energy is defined as energy that causes objects to move. If it has the ability to raise something, it is considered potential energy. However, it is the same energy that is presenting itself in different ways. Consequently, because the light is also only energy in motion, it may be referred to as “kinetic energy.”
Does light have kinetic energy?
When energy causes things to move, this is referred to as kinetic energy.
The light energy is a result of its motion. Because photons have no mass, their kinetic energy equals their total energy. So, the light has kinetic energy.
How to find kinetic energy of light?
Light, which is a kind of electromagnetic radiation, has kinetic energy.
The relativistic energy E of a particle od rest mass m0 and momentum p is given by
E2-p2c2 = m02c4
If the rest mass m0 of the particle is zero (such as for light also called as photons),
We have
E = pc or p = E/c
But p = νE/c2
νE/c2= E/c
hence, ν=c
It shows that the speed ν of a particle of zero rest mass is always equal to c, the speed of light.
Light is made up of particles with wave-like characteristics, such as photons. The idea of wave-particle duality is utilized to characterize this particular property of light that seems wave-like. The visible light wavelength ranges from 400 to 700 nanometres (nm).
Kinetic energy of light equation.
In order to calculate kinetic energy, multiply the mass by the square of the speed by the constant 1/2. This equation has two variables: the body’s mass (m) and its speed (v).
Its classical representation is as follow:
Ek=(1/2)mv2
And its relativistic representation is given by,
How do you find kinetic energy at the speed of light?
If anything moves at the speed of light, it will have an infinite amount of kinetic energy, which is greater than the entire Universe. The reason behind this is that nothing can move faster or at a quicker rate than light.
According to classical mechanics, the kinetic energy of a body is determined by the mass of the body as well as the speed of the body.
The mass multiplied by the square of the speed, and multiplied by the constant 1/2, equals the kinetic energy. The following is the equation:
Ek=(1/2)mv2
Where,
m = mass and v= speed (or the velocity) of the body
The following equation describes the relationship between an object’s classical kinetic energy and its momentum:
Ek=p2/2m
Where, P = momentum
To compute the kinetic energy of a body whose speed is a large fraction of that of light, one must use special relativity to account for the fact that the body is moving to the speed of light. It is important to comprehend how to use special relativity to problems involving high-speed particles in order to solve them.
To account for linear momentum in special relativity, we must modify the formula. The relativistic formulation for linear momentum utilizes m for rest mass, v, and v for velocity and speed, respectively, and c for the speed of light in vacuum, the relativistic expression for linear momentum is:
p=mγv
Where γ= Lorentz factor
Considering that an object’s kinetic energy is proportional to its momentum, we naturally see that the relativistic formula for kinetic energy would differ from its classical equivalent. As a matter of fact, the relativistic formulation for kinetic energy is as follows:
The equation demonstrates that the energy of an object approaches infinity when the object’s velocity v approaches the speed of light c . The conclusion is that an item cannot be accelerated past this boundary.
How do you find kinetic energy from momentum?
Kinetic energy is the quantity of energy that any material has as it accelerates, whereas momentum is the amount of mass that an item has when it is moving.
Multiply and divide R.H.S. by m
We know that p=mv. Substituting for mv in the above equation we get,
How are kinetic energy and momentum related?
There exists a correlation between kinetic energy and momentum because of their connections with mass and velocity
Using mathematics, the relationship between kinetic energy and momentum may be expressed as
As a result, we may state that a body’s kinetic energy is the relationship between a substance’s linear momentum and its kinetic energy that is being studied.
Because of the energy momentum relation, momentum increases directly with speed in a constant object, but Kinetic energy grows in direct proportion to the square of the velocity.
So, here in this article, we have studied what is the kinetic energy of light.
Reduce friction simply means the lowering the resistance of the body. There are many different types of approaches and methods to reduce friction. Let us see those methods in details.
First let us get some basic idea about the reduce friction.
Reduce friction:
The term “reduce friction” simply refers to “minimise the friction.”
A surface or an object experiencing friction is defined as the resistance they encounter as they are moved over another. This resistance created by the friction causes wear and tear between the surface which are in contact and hence it is necessary to reduce friction.
Different approaches and methods to reduce friction and their examples
1.By grinding the surfaces to a smooth finish.
Friction is created when two surfaces slide over one other. In terms of friction, the sticking mechanism at the microscopic size is the most important component to consider. Making the sliding surfaces smoother will help to lessen the amount of sticking.
There are three types of methods to smooth the surfaces
Grinding
Using sand papers
Chemical itching
Examples
Polishing the wooden furniture and sculpture
Removing corrosion with the help of chemicals
2.By making use of lubricants
Lubricants are chemicals that are applied to surfaces with the goal of reducing friction. It has the potential to minimise heat generation while also ensuring smooth sliding. Lubricants are usually semi-solid paste-like compounds that are used to minimise dry sliding friction by reducing frictional heat generation.
Examples
Lubricants in the engine components of an automobile.
The use of protective paints to keep metal from oxidising
Oiling the door hinges will make them easier to open and close.
Grease is used to keep bicycle parts moving smoothly.
A streamlined body aids in the reduction of friction, which is especially important in fluids. It makes it possible for the sliding body to travel through the medium with the least amount of resistance.
Examples
The streamlined bodies of fish and birds are copied in order to guarantee that there is as little friction as possible.
4. By using electrostatic magnetic levitation to reduce contact between surfaces
Friction can be reduced by reducing the amount of contact made during sliding. Through the use of magnetic levitation or charging both surfaces with the same polarity, we may significantly decrease touching.
5.By using sliding friction instead of rolling friction
Sliding friction is always larger than rolling friction, regardless of the situation. Consider the possibility of an automobile with square wheels. Friction created by rolling is used extensively in our daily lives.
Ball bearings are used to separate two bearing races by using balls as separators between the two races. The result is that sliding friction becomes rolling friction. The races will no longer glide over one another, but will instead pass the weight to the balls through rolling friction instead.
When compared to solid surfaces, fluids have lower coefficients of friction. Because they are very resistive to motion, fluids having a high density have a high coefficient of fluid friction. As a result, aeroplanes can move at far higher speeds than automobiles. In addition, when we apply lubricants or oil to surfaces, we are effectively changing dry friction into fluid friction, which is beneficial.
7. By reducing the amount of pressure or weight applied on the body
The amount of friction created is exactly proportional to the amount of normal force that is applied to the friction surface. The weight of the body acts as a normal force on the object due to the fact that we are on the surface of the planet. There will be very little or no friction in space. Selecting the right materials to decrease friction is so important.
Frequently Asked Questions (FAQ’s):
Q. What is reducing the friction?
Ans: Reduce friction simply means reducing resistance.
Smoothening of the surfaces which are in contact with each other to make them function easy and to avoid the production of frictional heat, is called the reduce friction.
Q. Why do we reduce friction
Ans: In some cases, it is necessary to make system work smoothly.
A necessary part friction is responsible for most of the wear and tear on working parts. Destroying the uniformity of the surfaces is one of its primary effects. Because of this, it is suggested that friction be reduced in specific circumstances.
Q. When would you want to decrease friction
Ans: It is sometimes essential to minimise friction in order to ensure safety from occurring.
The term “opposing force” refers to the fact that friction always acts in the opposite direction of a body that is moving or attempting to move. We aim at reducing friction where it is unnecessary. When machine parts are in contact with each other, friction reduces the efficiency of the machine; consequently, we oil them to minimise friction. Oil separates surfaces, which reduces friction between them.
Q. Reduce friction examples
Ans: Following is the list of examples of reduce friction
Walking on the ground
Cycling on the road
Vehicles braking system
Sanding
Train wheels
Trolley bag wheels
Roller skating
Lubricants in the hinges
Flying bird
Oiling the engines
Powder on carrom board
Q. Why do we increase or reduce the friction
Ans: Friction is the vital thing in our daily life and surrounding.
A firmer grasp on the object is required in order to maintain control over its motions. For example, if there is no friction on the road, the car would slip and will never come to a complete stop; thus, roads are constructed using concrete to enhance the amount of friction. However, it is generally important to lessen the friction in order to ensure that the machines operate as smoothly as possible. Consequently, depending on the requirements of the system under consideration, it is necessary to either enhance or decrease friction.
Q. Can we reduce friction to zero
Ans: We will never be able to entirely remove friction since it is required for any motion.
Without friction, we would be unable to picture any motion because there is no motion on a smooth surface. A substantial quantity of lubricants, such as oil, water, and grease, can be used to minimise friction to a great extent but it is not possible to completely eliminate friction.
Q. Does sand reduce friction
Ans:As the concentration of sand particles in the lubricated sliding contact rises, the friction and wear rates in the sliding contact increase proportionally.
Q. Does lubricant increase or decrease friction
Ans: Regular lubrication with oil or grease is required to decrease friction between machine components.
Lubrication reduces the amount of heat generated when two moving surfaces come into contact. Because it forms a film between two surfaces, it makes the process smoother and more efficient by reducing friction and so improving performance and efficiency.
Q. How do lubricants reduce friction
Ans: The term “lubricant” can be described as a material, such as grease, that when applied as a layer between two solid surfaces, reduces friction, heat generation, and wear and tear.
Lubricants are often organic in nature, and it is added to minimise friction between surfaces that are in mutual contact, which in turn lessens the amount of heat created when the surfaces move. Lubricants can also perform other functions such as conveying foreign particles, transferring forces, and heating or cooling the surfaces they come into contact with, among others.
Q. Does water reduce friction
Ans:Water is typically effective in reducing friction between two surfaces. In order to reduce friction between two surfaces, water must act as a barrier between the two surfaces. It does this by separating them and reducing the contact area between them. It can only accomplish this if none of the surfaces is absorptive; otherwise, the water will not be able to stay between the two surfaces.
Q. How will you decrease friction on your floors
Ans:The simpler way to decrease or reduce friction on your floors is by polishing the surface of the floors. By polishing the surface of the floor, roughness gets decreased and resulting into smooth surface.
Q. Does graphite reduce friction
Ans:Friction is reduced to an extreme degree by the lamellar structure of graphite. To prevent direct contact between the metals and the development of adhesion and scuffing during the friction process, solid graphite lubricant can be applied over the surface of the counterpart.
Q. Do ball bearings reduce friction
Ans: Ball bearing is the best example of rolling friction.
Whenever the axle rotates, the steel balls and wheel revolve in the opposite direction of the axle’s rotation. As a result, the rolling friction between the two cylinders is lower than the sliding friction between them. Bearings that roll rather than slide minimise friction as a result of the rolling friction that they generate.
Sliding friction is turned into rolling friction as a result of the usage of rollers and wheels in production. Because rolling friction is less than sliding friction, we may lower the amount of force necessary to move an item by using rollers and wheels. As a result, the object can be moved more readily when using rollers and wheels.
Q. Is there friction in the desert
Ans: It is difficult to walk on the desert sand.
Our feet and sand particles have less friction when we step on sand. While walking on the sand, our feet become slippery due to the rolling. As a result, walking on sand is more difficult due to the reduced friction.
Q. Does powder reduce friction
Ans: Sliding friction is the friction come into play when we use powder on any surface.
When talcum powder is dry, it has a minor friction-reducing effect on some materials against the skin, but when it is wet, it has the opposite effect. Additionally, powder is highly suggested and should be placed on the surface of the carrom board to smooth up the surface. Due to this striker and other coins of the game can easily slide.
Q. Does ice reduce friction
Ans:Sliding on ice or snow is significantly less difficult than sliding on most other surfaces, and no one denies that fact. However, although liquid water at the ice surface reduces sliding friction on ice, the current opinion is that this liquid water is not dissolved by pressure, but rather by the frictional heat created during sliding.
Q. Does rain increase friction
Ans:When water is present in sufficient quantities, it works as a lubricant. The quantity of rain that falls and the amount of standing water on the pavement can both have an impact on this change in elevation. Heavy rains may frequently reduce the coefficient of friction to 0.4, which is about half of what it would be on a dry pavement under normal conditions.
Q. Does tire tread reduce friction
Ans: Tire tread is meant to channel water away from the wheel when roadways are moist.
In rainy weather, when the roads are slick from rain or snow, tyre tread is designed to channel extra water away from underneath the wheel. This enables for the greatest amount of contact between the road and your tyre when it is most needed. To minimise dangerous slippage on snow and ice, winter tyres are even designed to have more gaps in the treads than regular tyres.
Q. Does car brakes reduce friction
Ans: Most of the car brakes employ friction between two surfaces to convert kinetic energy into heat.
Car brakes operate because of friction; the brake pads push down on the rotors, which causes the friction to slow the wheels. Friction is what causes brakes to work. Because it determines how much power is used to drive the rotors and pads together, the brake pedal has the ability to alter the degree of friction.
Q. How do air cushions reduce friction
Ans:An air cushion may be created on any flat surface, whether it is on land or in water, by trapped air currents! It is possible to glide effortlessly over the smooth surface underneath because of the cushion’s significant reduction in frictional resistance.
Q. How does water affect the friction of sand
Ans: The addition of a little amount of water but not too much to sand significantly reduces sliding friction.
Small quantities of water can generate capillary bridges, according to most experts. The shear modulus of the sand is increased by the creation of capillary water bridges, which makes sliding easier. When the capillary bridges become clogged with too much water, the modulus decreases, causing the friction coefficient to rise once again.
Q. Does chalk powder reduce friction
Ans:Magnesium carbonate, sometimes known as ‘chalk,’ is a substance that is used to improve the coefficient of friction.
The particles in talcum powder are tiny, but the particles in chalk powder are large. Friction is mostly caused by differences in surface area. Because talcum powder has a smaller surface area than chalk powder, it decreases friction, whereas chalk powder has a higher surface area and increases friction. There is less friction on a smaller surface area, hence it produces less friction.
Q. How does a hovercraft reduce friction
Ans:Slow-moving, low-pressure air vents or currents are ejected downward against the surface of the water below the hovercraft. It is possible to glide effortlessly over the flat surface underneath because of the cushion’s significant reduction in friction.
Q. How does oil reduce friction
Ans: Oil is introduced to the engine in order to minimise friction.
A thin coating of oil is created between the two surfaces when oil is placed between them. The oil coats the moving components’ surfaces, making them slippery as a result of the friction. When they brush against one other, the interlocking between the two surfaces is much decreased because of this layer. It is easier for them to slide over one another, resulting in less friction.
Q. How do you reduce friction in big machinery and cars
Ans:The use of lubricants such as oil and grease, as well as the use of ball bearings between machine elements, can help to reduce friction. A lubricant is a substance that is placed between two surfaces that are in touch with the goal of minimising friction between them.
Q. How to reduce friction between wood
Ans:The friction between the woods can be reduced by polishing the surfaces using the sand papers. Also, special lubricant called as varnish can lower the friction coefficient of several materials. The high static friction coefficient of these elastomers is a common characteristic. Coating with lubricating varnish can effectively reduce the stick-slip effect in actual use.
Q. Reduce friction between two surfaces
Ans: There are many ways to reduce friction between the surfaces in contact.
Polishing the surface helps minimise friction by smoothing out the surface. It is possible to minimise friction by using lubricants such as oil or grease, which may be applied to the surfaces. Ball bearings can be used to lessen the friction between a rolled object and the surface it is rolling on.
Q. What is the effect of reducing friction on a machine
Ans:Increasing the efficiency of a machine while simultaneously minimising the amount of hazardous heat generated between machine elements is the result of reducing friction on the machine. The excessive creation of heat will harm machine parts if friction is not reduced. Furthermore, if the friction isn’t decreased, the process will demand more power.
There is the external and internal force that could be studied depending on the type of work. Let us see in detail about is gravity an external force.
It is possible to have various forms of forces that will never affect the overall mechanical energy of an item but will instead just transfer the energy of an object from potential to kinetic energy (or vice versa). Internal forces and external forces are the two types of forces that may be found in a given circumstance.
In this article, we will study is gravity an external force or an internal force by comprehending the ideas of internal and external forces.
Is gravity an external force?
Gravity is not an external force.
The gravitational force or gravity between two particles in a system is defined as when two particles in a system are attracted to one another. When we investigate gravitational force, we are looking at the interaction of two or more particles. Moreover, the gravitational pull conserves the overall amount of energy. As a result, gravity is considered an internal force.
External Force Vs. Internal Force
Many classification systems are used to classify the various kinds of forces.
It was stated that all forces might be classified as contact or action-at-a-distance. A force’s classification as an action-at-a-distance force depends on whether it may exist even when objects are not physically touching. Even if two items aren’t physically touching, they can still be affected by forces like gravity, electricity, and magnetism.
It is possible that some types of forces, when present and when involved in the performance of work on things, will cause the total mechanical energy of the item to be altered. A force that can never have an effect on an item’s total mechanical energy, but can only transfer the energy of an object from its potential to its kinetic state, is referred to as a kinetic energy.
Internal forces and external forces are the two types of forces that may be found in a given situation. So, that means internal and external forces based on whether or not their existence has the capability of altering the overall mechanical energy of an object.
There are numerous excellent approaches to explain and distinguish internal and external forces. However, for the purposes of this discussion, we will logically conclude that external forces are comprised of the applied force, the normal force, the tension force, the friction force, and the air resistance force. However, internal forces comprise gravity, magnetic, electrical, and spring forces for our needs.
Non-conservative and Conservative forces
In order to understand the significance of classifying a force as either internal or external, it is necessary to understand how that type of force may modify the total mechanical energy of an item when it performs work on that object.
Non-Conservative Force:
A change in the total mechanical energy (KE + PE) of an item occurs when net work is performed on it by an external force. It is possible for an item to gain energy if the work is positive. It is possible for an item to lose energy if the work is negative. The increase or decrease in energy might take the form of potential energy, kinetic energy, or a combination of the two. In such conditions, the amount of work completed will be equal to the amount of mechanical energy that has been changed in the item.
“Nonconservative forces” refer to external forces that have the ability to modify the total mechanical energy of an object due to the fact that they have the power of affecting the total mechanical energy of an object.
Conservative Force:
It is possible for an object’s total mechanical energy (KE + PE) to remain constant even if the object’s principal source of net work is internal force (for example, gravitational and spring forces). When this occurs, the object’s energy takes on a different form. In the case of an object “forced” to drop from a high height to a low elevation due to gravity, part of the potential energy of the object is converted into kinetic energy as a result of gravity.
Conversely, the total amount of kinetic and potential energy remains constant during the experiment. Energy conservation is the term used to describe this.
However, when internal forces are the sole ones conducting the work, energy can alter forms, going from kinetic to potential (or vice versa), but the overall value of mechanical energy is conserved. It is for this reason that internal forces are sometimes referred to as conservative forces because they are capable of modifying the form of energy without increasing the total quantity of mechanical energy contained inside a system.
Internal forces – gravitational and spring forces – are the only ones that perform work on the items described in the following examples. This results in the transformation of energy from KE to PE (and vice versa), while the overall quantity of mechanical energy is preserved. How the energy is transferred between KE and PE should be the subject of each description.
1. If in the absence of air resistance, a ball falls from a height of 2 meters.
→ A decrease in height (dropping) and an increase in velocity are being experienced by the ball. In order to do this, the internal or conservative force (gravity) is used to convert energy from Potential Energy (height) to Kinetic Energy (velocity).
2. When a dart is launched from its original resting position, the spring of a dart gun exerts a force on the dart.
→ After undergoing a transition from a compressed to a relaxed condition, the spring is forced forward, propelling the dart onward. This transition causes the internal or conservative force (spring) to transfer energy from Potential Energy (a compressed spring) to Kinetic Energy (speed).
Frequently Asked Questions (FAQs):
Q. What do you mean by an external force?
Ans: Any body can feel force externally or internally.
An external force is defined as the force applied to an item from the outside. It can be either a contact or a non-contact force. An external force is mostly a contact force, which occurs when an item interacts with its environment.
When a force operates on a system internally, it is referred to as an internal force. This force either causes a change in the system or opposes a change in the system caused by an external force. In a system, internal forces are generated within the system, and they are unable to cause an external change in the system, such as an acceleration of the system or a change in the system’s kinetic energy.
In physics, the term “non-contact force” is used to describe the force that a body may exert on another body without actually coming into physical touch with it.
Following is the list of non contact force examples that we can see in our surrounding.
Let’s take a closer look at each of the non contact force examples above.
Non contact force examples
Clothes from dryer:
You must have observed the static cling on clothes. This is because of the triboelectric effect which comes under electrostatic force and is type of non contact force. Triboelectric effect causes the static charge on your dryer’s clothing to become negative as various materials with varying affinities for electrons tumble together. This causes materials with a stronger affinity for electrons to lose electrons and become positively charged.
For a period of time while the clothes are drying, the initially humid environment provides a relatively conductive electrical path for static electricity to dissipate. However, as the clothes dry and the relative humidity in the dryer drum falls to extremely low levels, the air in the drum becomes highly resistive, causing the static charges generated by the dryer’s tumbling action to accumulate more quickly than they can be dispersed.
Sugar in plastic jar:
Sugar is the most prevalent component in every kitchen, and we all have a lot of it. If you look at the sugar that is kept in a plastic jar, and if that plastic jar is transparent, you may notice that the sugar has adhered to the inside of the plastic jar. This occurs as a result of the electrostatic force that is formed between the plastic jar and the sugar crystals. Herein the case, this electrostatic force is simply a non contact force.
Attraction of paper pieces on comb:
This is one of the most straightforward, but effective, noncontact force examples. Aside from that, this is one of the most typical demonstrations used in schools to demonstrate how static electricity is produced. When we rub the comb or balloon on our hair and then bring it close to the little bits of paper, we can see that the paper pieces are drawn to the comb or balloon and disappear. This demonstrates that a non-contact force, in the form of electrostatic force, is there.
Solar system:
We all are familiar with the words ‘Solar system’. The gravitational force of the sun draws the planet toward it, causing the straight line of direction to transform into a curved line. Consequently, the planet continues to move in an orbit around the sun. In our solar system, the sun’s gravitational pull causes all of the planets to rotate around it. This force so called gravitational force is a form of non-contact force that acts between the sun and the other planets of the solar system.
While playing on the ground with ball we often throw the ball in order to pass it to another person. When we do so, then after reaching to certain height the ball falls back on the ground. The ball is falling to the ground as a result of the gravitational pull of the earth acting on the ball during its flight. This gravitational force between the ball and the ground is a type of non contact force which pulls the ball in downward direction.
Leaf fall:
In the autumn season, we usually observe the falling of faded leaves. When the tree’s leaves fall, they always falls on the ground or surface of the earth. This fall is simply because of the gravitational force which is a type of non contact force, acting between the leaves and the ground or surface of the earth. Earths gravitational force always attracts the bodies towards it. Leaf fall is the best and common non contact force example.
An amusement part is incomplete without the roller coaster ride. Roller coaster ride need some applied force through the form of electrical motor to reach up to certain height. After reaching that height, roller coaster is set free to work on the gravitational force alone. This working of roller coaster with gravitational force is simply a non contact force.
A door catch:
When it comes to kitchen cabinets or other types of cabinets and the doors, a magnetic catch is typically employed to keep the door closed. The working of door catch is efficient than the other traditional latches. Here, the working of magnetic force shows the type of non contact force.
Magnetic levitation trains:
Magnetic levitation trains also called as maglev trains worked on the powerful electromagnets. The fundamental principles of magnetism are used to make these trains float over guideways, rather than the traditional steel wheel and track locomotives. Because there is no friction between the rails, these trains may run at speeds of hundreds of miles per hour or more. But speed isn’t the only benefit of maglev trains. Because the trains hardly (if ever) touch the track, there is far less noise and vibration.
Maglev trains are less vulnerable to weather-related delays due to reduced vibration and friction. As a key contrast between them and conventional trains, magnetic levitation trains (maglev trains) do not have an engine, at least not the type used to accelerate standard train carriages over steel tracks. It functions only on the basis of magnetic force, which is a form of non-contact force.
Iron is a magnetic material, and iron pins are created from it. Magnets are attracted to iron because of the impact of their magnetic field on the iron’s magnetic properties. The iron pins stick to each other below the pole of a magnet because the magnet creates magnetism in the iron pins, which is attracted to the magnet and clings to it as a result of the magnetism.
By magnetic induction, the magnetised pins magnetise and attract the other pins in the vicinity of the magnetised pins. Therefore this magnetization and attraction of an iron pins becomes a non contact force example.
Navigation compass:
You must have seen the navigation compass which works on magnetism. The red pointer on a compass is actually a magnet, and it is being drawn to the Earth’s natural magnetism, which is referred to as the geomagnetic field. The Earth operates like a huge bar magnet, with one pole located in the Arctic (near the north pole) and another located in Antarctica (near the south pole).
For example, if the needle in your magnetic compass is pointed north, this indicates that it is being pulled (attracted) toward anything near the Earth’s north pole. Since opposite poles attract, your compass must be drawn to a magnetic south pole. That is, the magnetic north pole of Earth is really the magnet’s south pole. So this becomes one of the good non contact force example.
We all enjoy the rainy season. Because of the force of gravity, raindrops and all other falling items are pulled to the surface of the Earth. This action of gravity is simply a type of non contact force. However, the procedure that raindrops travel through in order to arrive at the place where they fall is a little more complex than a basic gravitational impact alone.
In order to produce rain, water must first become a gas, rise into the atmosphere, and then return to a liquid state again. The droplets subsequently yield to gravity and fall from the clouds. The hydrologic cycle is the collective term for the process through which water turns into rain and falls.
Electrostatic force: Electrostatic force is the force that arises between two charged objects when they come into contact. Everything is composed of microscopic positive, negative, and neutral particles; opposite charges attract one another and similar charges repel one another; this is the consequence of electrostatic forces acting on the particles.
Gravitational force: There is a gravitational pull between all objects that have mass in them. It is a universal force that pulls items in the direction of one another. Everything is drawn toward the centre of the Earth by the gravitational attraction of the Earth’s gravity.
Magnetic force: When two magnetic fields come into contact with each other, they create magnetic force. Magnetic forces can be either pull (attraction) or push (repulsion) forces, depending on the type of moving charge on a metal object.
Nuclear force:Nuclear force is classified into two types: strong nuclear force and weak nuclear force. In a nucleus, there is a short-distance force called the strong nuclear force, which occurs between basic particles. It is not affected by charge and may be used between protons and protons, neutrons and neutrons, and protons and neutrons, among other situations. When a neutron decay takes place, the weak nuclear force is responsible for mediating the process, which results in the production of a charged particle and an uncharged particle known as a neutrino.
Q. State the difference between contact force and non contact force.
Ans: The following table illustrates the difference between contact force and non contact force.
Contact force
Non contact force
This force is only produced when two separate things come into touch with one another.
If there is no contact between the two items, then a non-contact force is produced by either attraction or repulsion between the two things.
The field and the contact force have no connection or physical contact to one another.
The presence of non-contact force is usually accompanied by the presence of a different types of the field.
Contact forces are classified into the following categories: applied force, spring force, normal force, air resistance force, frictional force, and buoyance force.
Other than contact force, there are other sorts of non-contact forces. These include electrostatic force, gravitational force, magnetic force, and nuclear force.
The contact force examples are glass of water on the table, hovering mouse, bungee jumping, suspension bridge, airplane in the sky, wooden block floating in water, sliding in playground, jar opening etc.
Non contact force examples are throwing a ball, solar system, attraction of iron pins, attraction of paper pieces to hair comb, leaf fall, magnetic levitation train, roller coaster ride etc.
There are a variety of contact force examples that can be seen in our surroundings. Whenever two items come into contact with one another, the term force is used to describe the push or pull that happens.
Let us see a list of contact force examples as below:
These are the various and simple contact force examples that we see and experiences in our day-to-day life. A contact force is a force that acts between two bodies that are in contact with one another. Let us take a look at each of them in some detail.
Contact Force Examples
A glass of water:
People usually tend to see this type of contact force examples on an hourly basis around them as they keep on lifting the glass to drink water and then putting back on the table. Here glass is in contact with the flat surface where the contact force is simply acting in the form of the normal force.
The food kept on the shelves of the refrigerator experiences the normal force. This is the force exerted on the body at rest which is nothing but food in this case. As this food is in contact with and hence it experiences the normal force.
When you or any other person around you stands on the ground, they are being in contact with the surface of the ground. Hence our body experiences the normal force which is because of the contact force and is being exerted by the ground.
Table lamp:
We all have the table lamp on our study table or on the office table. The lamp in the resting position kept on the table experiences the normal force. This force is exerted on the table lamp by the table as a result of contact force.
This is one of the most common contact force examples. We all use a mouse attached to the computer or laptop for our work, study, and many other purposes. The mouse is basically used to hover the pointer on the screen to select the menu or other options we want.
In order to hover the screen pointer of the mouse, you have to physically move the mouse by using your hand. This is nothing but you are making contact with the mouse to apply some force on it. This applied force is nothing but one of the types of contact force.
Pressing a key on thekeyboard:
Just like the mouse, the keys from a keyboard of the computer or laptop need to get pressed so that the command will appear on the screen of the respective devices. In this process, we are simply applying force by making contact with fingers on the keyboard. Hence the contact force plays a role in the form of applied force.
Bungee jumping:
Bungee jumping is one of the adventure sports where you can feel the proper tension force and spring force is created within the rope and the human body. In this person, feet are tied to the end of the rope and the other end is tied to the support located at some height. When the person jumps off the edge, he/she goes down and then at some point gets in the upward direction. This happens because of the tension force and spring force created by the contact between the rope and the feet of the person.
Car towing:
You often have observed that when the car is parked at the wrong places, gets towed. For towing purposes, one needs to lift and hang the car on the hook of the tow vehicle. This contact between the tow and car is nothing but the tension force which is being created while lifting them up. Tension is simply a pulling force.
In the case of a suspension bridge, the contact force is simply compression and tension. Compression, also known as compressive force, which operates on something in order to compress or shorten the item on which it acts. Tension, also known as tensile force, is a type of force that operates to expand or lengthen the object on which it acts.
To initiate the fire, we must rub the wooden stick of the matchbox on the material coated on the box. By doing so we are creating friction between stick and coated material. This can only happen because of the contact force.
Furniture shifting:
When we are shifting the furniture, we are simply applying the force to the furniture. The furniture is always in the contact with ground or floor. When the frictional force which is also a contact force in this case is less then by the applied force, we can easily shift the furniture wherever we want.
Slides on the playground:
Children often enjoy the slides in the playground. When one is sliding down the slide, it is because of the friction force which is a contact force. Also, the children get slow down at the end of the slide because of the frictional force changing into gravity.
Kicking football:
While playing football one passes the ball to another person. To pass the ball, it is necessary to kick the ball, and to do so one must apply the force through the leg on the ball. Here contact force that acts between the feet and the ball is simply the applied force.
To open the bottle or the jar, we need to twist the top lid. For twisting, we need to apply the force on the lid which means that, here in the case of twisting the contact force is the applied force.
Chair pull:
In order to sit anywhere near the office table, dining table, or any other place, first, we have to pull a chair. When the chair is at rest, the normal force is being exerted on it by the floor or ground. However, while pulling purpose we need to apply the force on the chair. Therefore, in this situation, there are two types of contact forces acting on the chair which are the normal force and the applied force.
Bicycle ride:
Everyone loves to ride a bicycle for exercise as well as roaming purposes. To ride a bicycle, one needs to apply the force on the pedal which then results in movement of the bicycle. Also, there is always a frictional force constantly acting between the tyre of the bicycle and the road. So, when the person is riding a bicycle, there are two types of contact forces that come into play and that are the applied force and the friction force.
Have you ever traveled by the airplane? If yes then you must have felt the friction that is occurring on the exterior part of the airplane and clouds and air. The force exerted on an item when it comes into contact with air while passing through it is known as the air resistance force. It is the result of friction between the air and another item. Here, in this case, this air resistance force is simply the contact force.
When the person throws an object in the water, it floats. Similarly, when you put a wooden block in the beaker containing water, it floats at the surface of the water. There is a buoyance force or upthrust force acting between the piece of that wooden block and water. This force is the contact force in this case. Depending on the parameter of buoyance force or upthrust force, the object can immerse or float in the liquid.
These all are the list of contact force examples in our surroundings.
Frequently Ask Questions (FAQ’s):
Q. What do you mean by contact force?
Ans: The force where it needs some physical contact to occur.
For the purposes of this definition, contact forces refer to forces that act between two objects that are physically in contact with one another.
Q. What is the basic difference between contact force and non-contact force?
Ans: The difference is just based on the word contact.
The contact forces can only be produced when there is physical activity on the item or an object. However, the non-contact force is the one where no physical activity needs to be done on the object, they are not visible.
Air resistance force: The force that comes into play on an item when it comes into contact with air while passing through it is known as the air resistance force.
Frictional force: It is often known as friction, which is a force that works against the movement of an object.
Applied force: It is called applied force when someone or something applies force to another item in a direct manner, resulting in the object moving.
Spring force: The force generated when an external force forces a spring to alter its form is known as spring force or spring tension.
Normal force: The force that holds things in place while they’re lying on a stable surface is known as “normal force.”
Tension force: Tension acts as a compulsion. As a result of the tightening of both ends of things such as wires, ropes, cables, and rods.
When it comes to understanding the concept of normal force with mass, we need to delve into the fascinating world of physics. Normal force is the force exerted by a surface to support the weight of an object resting on it. In this blog post, we will explore how to calculate normal force with mass, including the role of gravity, the equation for finding normal force, and various factors that affect it. So, let’s dive in and unravel the mysteries of normal force with mass!
Calculating Normal Force with Mass
The Role of Gravity in Determining Normal Force
Before we delve into the calculations, it’s important to understand the role of gravity in determining the normal force. Gravity is the force that pulls objects towards the center of the Earth. When an object is at rest on a surface, the force of gravity acts vertically downwards. The normal force, on the other hand, acts perpendicular to the surface and counteracts the force of gravity. It prevents the object from sinking into the surface or falling through it.
The Equation for Finding Normal Force with Mass
To calculate the normal force with mass, we can use the equation:
The mass is measured in kilograms (kg), and the gravity is typically taken as 9.8 m/s^2 on the surface of the Earth. By multiplying the mass of an object by the acceleration due to gravity, we can determine the normal force acting on it.
Worked Out Examples on How to Find Normal Force with Mass
Let’s work through a couple of examples to solidify our understanding.
Example 1:
Suppose we have a block with a mass of 10 kg resting on a table. What is the normal force acting on the block?
We can use the equation we mentioned earlier:
Substituting the given values, we get:
Therefore, the normal force acting on the block is 98 N.
Example 2:
Let’s consider a person with a mass of 60 kg standing on a bathroom scale. What is the reading on the scale?
Again, we can use the equation:
Plugging in the values, we have:
Therefore, the reading on the bathroom scale would be 588 N.
Factors Affecting Normal Force
The Impact of Angle on Normal Force
The angle at which an object is placed on a surface can affect the normal force acting on it. When an object is on an inclined plane, the normal force is not equal to the object’s weight. Instead, it can be calculated using trigonometry. The normal force can be determined by multiplying the weight of the object by the cosine of the angle of inclination.
The Effect of Friction on Normal Force
Friction plays a crucial role in determining the normal force when there is relative motion or an impending motion between two surfaces. In such cases, the normal force can be reduced due to the opposing force of friction. The magnitude of the frictional force depends on the coefficient of friction, which is a measure of the friction between the two surfaces.
The Influence of Applied Force on Normal Force
When an external force is applied to an object, it can affect the normal force acting on it. If a force is applied in a direction perpendicular to the surface, it can alter the normal force. For example, if you push down on an object, the normal force will increase. Conversely, if you pull up on an object, the normal force will decrease.
Advanced Concepts in Normal Force
How to Determine Normal Force with Mass and Acceleration
In some cases, we may need to calculate the normal force when an object is accelerating. To do this, we need to consider the net force acting on the object. The net force is the vector sum of all the forces acting on the object. When an object is accelerating, the net force is given by the product of the mass and acceleration. The normal force can then be calculated by subtracting the force due to gravity from the net force.
How to Measure Normal Force with Mass and Coefficient of Friction
In situations where there is friction between two surfaces, the normal force can be determined by considering the force of friction. The force of friction can be calculated by multiplying the coefficient of friction by the normal force. Rearranging this equation, we can solve for the normal force by dividing the force of friction by the coefficient of friction.
Worked Out Examples on Advanced Concepts
Let’s explore a couple of examples involving advanced concepts of normal force.
Example 3:
Suppose we have an object of mass 5 kg experiencing an acceleration of 2 m/s^2. What is the normal force acting on the object?
Using the equation for net force:
Substituting the given values, we have:
Since the object is not accelerating vertically, the net force acting on it must be equal to the normal force. Therefore, the normal force is 10 N.
Example 4:
Consider a box with a coefficient of friction of 0.4. If the force of friction between the box and the surface is 20 N, what is the normal force acting on the box?
Using the equation for force of friction:
Rearranging the equation to solve for the normal force, we get:
Therefore, the normal force acting on the box is 50 N.
Understanding how to find normal force with mass is crucial when it comes to analyzing the forces at play in various situations. By considering the role of gravity, applying the equation for finding normal force, and being aware of the factors that affect it, we can accurately determine the normal force acting on an object. So, whether you’re studying physics or simply curious about the world around you, the concept of normal force with mass is an important piece of the puzzle that allows us to better understand the forces that shape our everyday experiences.
Can the normal force be at an angle? How does understanding normal force at an angle relate to finding normal force with mass?
The concept of normal force is commonly associated with finding the force exerted by a surface on an object. However, it is important to understand that the normal force can also exist at an angle. This understanding is crucial when exploring the relationship between finding normal force with mass and analyzing situations where the normal force is not purely vertical. To gain insights into the complexities of normal force at an angle, it is recommended to refer to the article on Understanding normal force at an angle. This article provides in-depth information about situations where the normal force deviates from being purely perpendicular to the surface, shedding light on how to accurately calculate and interpret such forces.
Numerical Problems on how to find normal force with mass
Problem 1:
A car of mass is moving on a horizontal road with a constant velocity. Find the normal force exerted by the road on the car.
Solution:
The normal force ) exerted by the road on the car is equal in magnitude and opposite in direction to the gravitational force ) acting on the car. Therefore, we can calculate the normal force using the equation:
where: = mass of the car
Problem 2:
A block of mass is resting on a horizontal surface. Determine the normal force exerted by the surface on the block.
Solution:
When an object is at rest on a horizontal surface, the normal force ) exerted by the surface on the object is equal in magnitude and opposite in direction to the gravitational force ) acting on the object. Thus, we can calculate the normal force using the equation:
where: = mass of the block
Problem 3:
A person of mass is standing on a weighing scale inside an elevator. Calculate the normal force exerted by the scale on the person when the elevator is:
a) Accelerating upwards with acceleration
b) Accelerating downwards with acceleration
c) Moving upwards with constant velocity
d) Moving downwards with constant velocity
Solution:
a) When the elevator is accelerating upwards, the normal force ) exerted by the scale on the person is given by:
where: = mass of the person = acceleration due to gravity = acceleration of the elevator
b) When the elevator is accelerating downwards, the normal force ) exerted by the scale on the person is given by:
where: = mass of the person = acceleration due to gravity = acceleration of the elevator
c) When the elevator is moving upwards with constant velocity, the normal force ) exerted by the scale on the person is equal in magnitude and opposite in direction to the gravitational force ) acting on the person. Thus, we can calculate the normal force using the equation:
where: = mass of the person
d) When the elevator is moving downwards with constant velocity, the normal force ) exerted by the scale on the person is equal in magnitude and opposite in direction to the gravitational force ) acting on the person. Thus, we can calculate the normal force using the equation:
is moving on a horizontal road with a constant velocity. Find the normal force exerted by the road on the car.
) exerted by the road on the car is equal in magnitude and opposite in direction to the gravitational force 
) acting on the car. Therefore, we can calculate the normal force using the equation:
= acceleration due to gravity