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Kinetic Energy

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Last updated date: 22nd Mar 2024
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What is Kinetic Energy?

Kinetic energy is defined as the energy that is produced by an object due to its motion. When an object is set to acceleration, there is a definite need to apply certain forces. The application of force needs work, and after the work is done, the energy gets transferred to the object making it move at a constant velocity


Here, the energy transferred is referred to as kinetic energy and depends on the speed and mass of the object being set in motion.


Fun Facts: As we move ahead on this page, you will understand how energy in an object changes from one form to another. For instance, take a flying squirrel that has collided with a chipmunk in its rest state. After the collision, there will be a flow of kinetic energy resulting in the squirrel to transform its energy into some other forms. It will come to rest and then the kinetic energy will be zero.


How Can We Calculate Kinetic Energy?

In order to find out the kinetic energy, there needs to be some reasoning platform. Some of the findings are required, like the work done (W), by force (F). So, for instance, consider a box of mass m that is being pushed to a distance d because of the application of a force parallel to the surface. 


Looking at the definition of work done, it is the product of force and distance.


W​=F⋅d


    =m⋅a⋅d​


From the kinematic equations of motion, it is stated that we could substitute the acceleration a if the initial and final velocity v and v0​ and the distance d. Is given:

So, from that, we derive: 


\[ v^{2} = v_{0}^{2} + 2ad \]


gives us, \[a = \frac{v^{2} + v_{0}^{2}}{2d}\]


When a net amount of work is done, the kinetic energy K does change.


Kinetic Energy: \[ K = \frac{1}{2} m v^{2}\]


In other words, the change in kinetic energy is equal to the net work done on a system or an object.


\[ W _{net} = \triangle K \]


The above-mentioned formula is said to be the work-energy theorem and applies in a general sense. When forces act in different magnitudes and directions, it is imperative to know the conservative forces and conservation of energy. Here, the conservative force is a force where the total work done in any moving object between two definite points is independent of the path taken. Whereas, the conservation of energy states that the sum total energy of any isolated system doesn’t change over the time.


Examples of Kinetic Energy and Potential Energy


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Kinetic Energy Examples

Bearing in mind the above formula for kinetic energy, look at a few of the examples seen in everyday life situations. 

  1. An aeroplane has huge kinetic energy in flight because of its faster velocity and huge mass.

  2. A baseball after it is thrown, it will have a large amount of kinetic energy because of its high velocity, and despite its smaller size and mass.

  3. A downhill skier coming down from above will show immense kinetic energy because of its high velocity and mass.

  4. Before a golf ball has been struck shows zero kinetic energy as its velocity is zero.

  5. When an asteroid falls at an incredible speed, it has a huge amount of kinetic energy.

  6. A car travelling down the road has less kinetic energy as compared to that of a semi-truck because of the less mass of the car than the truck.


What is Potential Energy?

The form of energy by virtue of which energy is stored in an object due to some position and relative to some other position at rest is known as potential energy. Three types of energy effects are shown here viz: nuclear energy, chemical, and potential electrical. This can be measured based on the distance, height, or mass of the object. It is measured in Joules.


Examples of Potential Energy:

  1. A rocket sitting at the cliff's edge. When the rock falls, the potential energy gets converted to kinetic energy.

  2. Tree branches up high can fall into the ground, so they have potential energy.

  3. A dynamite stick has chemical potential energy. After the release, it will get fused to contact with the chemical; it will be activated.

  4. Foods that we intake provide us with energy due to the chemical potential energy. It helps with basic metabolic activities inside us.

  5. A spring stretched in a pinball machine can move the call after it is released. This produces elastic potential energy.

  6. Crane, when swings in a wrecking ball gain much energy even to crash the buildings


Kinetic Energy Units

When we take the unit of mass as kilogram and velocity as a metre per sec, the kinetic energy has the unit of kilograms metre square per Second Square. It is usually measured in Joules. So, the SI unit of kinetic energy is Joule (J), which is precisely 1kg.m2.


Conclusion

Kinetic energy is the energy generated by an object as a result of its motion. There is a clear necessity to apply forces when an item is set to accelerate. Work is required for the application of force, and after the work is completed, the energy is delivered to the object.

FAQs on Kinetic Energy

1. What is kinetic energy, and how does it work?

Kinetic energy is the energy created by an object as a result of its motion. When an object is set to accelerate, it is imperative that specific forces be applied. Work is required to apply force, and once the work is completed, the energy is transmitted to the object, causing it to move at a constant velocity.


The energy transported is known as kinetic energy, and it is determined by the speed and mass of the object being moved.


Facts to remember: You will learn how energy in an object moves from one form to another as we progress down this page. Take, for example, a flying squirrel that has collided with a chipmunk when it is resting. There will be a flow of kinetic energy after the collision, causing the squirrel to shift its energy into various forms.

2. What is interesting about kinetic energy?

Some of the fun and interesting things on kinetic energy were derived through its equation is given as:

  • Kinetic energy relies on the object's velocity, and when the object doubles, the energy quadruples. 

  • It is not a vector unit, and the direction here doesn't matter. It only depends on the velocity with which it is thrown.

  • It should be either be o or +ve and the velocity should be +ve, or -ve

3. What are the various examples of kinetic energy?

Examples of Kinetic Energy


Consider a few instances from everyday life using the following kinetic energy formula.

  • Because of its higher velocity and mass, an aeroplane has a lot of kinetic energy while flying.

  • Because of its high velocity and despite its modest size and mass, a baseball will have a substantial quantity of kinetic energy after being hurled.

  • Because of its great velocity and bulk, a downhill skier coming down from above will produce enormous kinetic energy.

  • The kinetic energy of a golf ball before it is struck is 0 since its velocity is zero.

  • An asteroid has a lot of kinetic energy when it falls at such a fast pace.

  • The kinetic energy of a car driving down the road is lower than that of a semi-truck because the automobile has less mass than the truck.

4. What are the various kinds of kinetic energy?

Kinetic energy can be applied to anything that moves. The greater the kinetic energy of a thing, the faster it moves.


You'll find five different types of kinetic energy here.


a. Radiant Energy


Radiant Energy is a type of energy that comes from the sun. This is a sort of kinetic energy that is created when something moves across a medium or through space. Ultraviolet and gamma rays, for example.


b. Thermodynamic Energy


This is also known as heat energy, and it is produced when atoms clash with one another at a faster rate. Hot springs, heated swimming pools, and so on.


c. Energy of Sound


This is caused by the vibration of the object. It can pass through any medium except vacuum since there are no particles in vacuum. Tuning forks, banging drums, and other instruments are examples.


d. Electrical Energy


Free electrons (both +ve and –ve charges) provide this form of energy, batteries, etc.


e. Mechanical Energy


The sum of potential and kinetic energy is called mechanical energy. This energy can neither be created nor be destroyed and only can be transferred from one to another form. Its ex: a moving car, orbiting a satellite around the earth's orbit.

5. What is the definition of potential energy?

Potential energy is a type of energy in which energy is stored in an object as a result of its position in relation to another position at rest. Here are three sorts of energy effects: nuclear energy, chemical energy, and potential electrical energy. This can be calculated using the object's distance, height, or mass. Joules are the units of measurement.


Examples of Potential Energy:

  1. A rocket perched on the edge of the cliff. The potential energy in the rock is transformed into kinetic energy when it falls.

  2. Tree branches that are high in the air have the potential to fall into the earth, giving them energy.

  3. Chemical potential energy exists in a dynamite stick. It will be fused to contact with the chemical after the release, and it will be activated.

6. What is the formula for calculating kinetic energy?

There must be some sort of reasoning platform in order to determine the kinetic energy. Some of the findings, such as the work done (W), are mandated by law (F). Consider a box with mass m that is being pushed to a distance due to the application of a force parallel to the surface.


Work done is the product of force and distance, according to the definition.


W.d =F × d


        =M.a ×d


According to the kinematic equations of motion, we can substitute the acceleration a for the beginning and end velocity v and v0, as well as the distance d:


As a result, we can deduce:


\[ a=\frac{v^{2}v_{0}^{2}}{2d} \]


The kinetic energy K changes when a net amount of work is done.


\[K = \frac{1}{2} m v^{2} \] Kinetic Energy


In other words, the net work done on a system or an item is equal to the change in kinetic energy.


\[ W_{net} =\triangle K \]


The above-mentioned formula is known as the work-energy theorem, and it is applicable in a broad sense. It's critical to understand the conservative forces and energy conservation when forces act in diverse magnitudes and directions. The conservative force is defined as a force that causes the total effort done by any moving object between two distinct points to be independent of the path taken. The conservation of energy, on the other hand, states that the total energy of an isolated system does not change over time.

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