# Difference between Potential Energy and Kinetic Energy

There are several kinds of energy that we have often heard of. Energies like kinetic energy, gravitational energy, potential energy, etc., have been often put to use by us during various experiments. Potential energy and kinetic energy are some important energy sources that we have heard in our physics lectures. These students in various experiments use these energies. Kinetic and potential energy is also used by kids while playing. So, let us discuss these terms separately.

Potential energy is defined as an object's energy in response to the other object under stressed circumstances. In this energy, the object is placed under different circumstances wherein it acts differently. One of the important types of potential energy is gravitational energy. Gravitational energy depends upon the mass of an object with another object's mass and the distance on which the other object is placed. The SI unit of potential energy is Joule, and symbolically it is written as 'J.'

William Rankine, a Scottish engineer, invented the term potential energy in the 19th century. His research experiments were based on Aristotle's theory of potentiality. Potential energy is dependent upon the initial and final positions of the body that is under motion. Vectors represent the potential energy of an object. One of the examples of potential energy includes bow and arrow. When the force is applied to bow's string, the chemical energy gets transformed into potential energy, thereby applying the force to the arrow.

There are several kinds of potential energy like elastic potential energy, gravitational potential energy, electric potential energy, etc. Every potential energy has some distinctive features. There is chemical potential energy as well, which is defined as the energy stored in fossil fuels.

The forces derived from potential energy are called conservative forces. The following formula calculates conservative force.

W = -U

In the formula mentioned above, the U stands for the potential energy associated with the force. Potential energy helps in restoring forces like that of a string, spring, or gravitational force. We can see potential energy almost in every state. For instance, potential energy is present in gravity; potential energy is present between two bodies. The electrostatic forces between two bodies also come under the potential energy. So, let us discuss these kinds of potential energy separately.

Now, potential energy for gravity is defined as the process used to calculate small changes in height. The formula for calculating gravitational potential energy is;

Ug = mgh,

In the formula mentioned above, m represents the mass in Kg; g depicts gravitational field; h is the height, and U is the energy.

Well, in physics, gravity always exerts a downward force. This force is exerted on the center of the mass that is moving towards the earth's surface.

Talking in terms of the gravitational force between two bodies; it is calculated by:

U = - GMm/ r,

The negative sign depicts that the force is gained when the potential energy is lost. Having discussed the gravitational potential energy, let us discuss some points about chemical potential energy. The arrangement of atoms and molecules is called chemical potential energy. For instance, when a fuel is burnt, the chemical energy released is converted into heat, and thus, chemical potential energy is released.

Potential energy is present in all forces. There are other potential energy types like nuclear potential energy, electrostatic potential energy, magnetic potential energy, etc. These kinds of potential energy help in calculating the force of the mass. Thus, potential energy is one of the important forms of energy in the field of science.

Well, there is one more kind of energy that is important, i.e., kinetic energy. Kinetic energy is the kind of energy that an object possesses because of its motion. The force exerted on an object to move it from the position of rest to the position of motion. An object that has gained this kinetic energy tends to maintain it unless the speed changes. Now, let us see some historical points regarding kinetic energy.

1. The word kinetic has been derived from the Greek word 'kinesis,' which means motion.
2. Gottfried Leibniz and Johann Bernoulli, researchers of kinetic energy stated that 'kinetic energy is a living force.' And they proved this by their experiment and research wherein objects of different weights were dropped from different heights to know their kinetic energy.
3. The term kinetic energy was first used in the 19th century. In the year 1829, Gaspard Coriolis published a thesis paper named ' Du Calcul de l'Effet des Machines'. This work focussed on the calculations of kinetic energy used in mathematics.

So, these are some historical points regarding kinetic energy. Kinetic energy can be understood by the change of energy in an object. Kinetic energy is dependent upon the relationship between the object and its motion. This kind of energy can be passed from one object to another. It is interesting to note that Newton's second law is applied for calculating kinetic energy. The formula for Kinetic Energy is as follows:

K. E = 1/ 2 mv2

The S.I unit of kinetic energy is Joule (J), and the following formula represents it:

1 kg.m2.s-2.

Well, it is interesting to note that there are several types of kinetic energy. Some of the types include:

• Sound Energy: Sound Energy is defined as the energy produced due to the vibration of an object. Sound travels through a medium. The beating of drums is one of the popular examples of sound energy.
• Thermal Energy: Thermal Energy is defined as the heat energy generated when the atoms collide with each other. The hot water bath is one example of thermal energy.
• Radiant Energy: Radiant Energy is defined as the energy wherein the object is in motion and travels through a medium or space.

These are some types of kinetic energy wherein the position and motion of the object change. Now, let us discuss the difference between potential energy and kinetic energy.

S.NO. POTENTIAL ENERGY KINETIC ENERGY
1. Potential energy is defined as an object's energy in response to the other object under stressed circumstances. Kinetic energy is defined as the kind of energy that an object possesses because of its motion.
2. Potential energy cannot be transferred from one object to another. Kinetic Energy can be transferred from one object to another.
3. The factors of potential energy include height, weight, gravity, and mass of the object. The factors of kinetic include the speed and velocity of an object.
4. Potential energy depends upon the position and condition of an object. Kinetic energy depends upon the motion of an object.
5. Example: A ball at a particular height possesses potential energy. Example: A ball dropping from a height possesses kinetic energy.

So, these are some of the key differences between potential and kinetic energy. Both potential and kinetic energy have distinctive features and are dependent upon several factors. Thus, potential and kinetic energy are two important kinds of energies used both academically and on a daily basis.

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