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# Difference Between Kinetic Energy and Potential Energy

Kinetic Energy vs Potential Energy

Kinetic Energy and Potential Energy are the two states of energy. Energy exists in universe in many forms such as solar energy, thermal energy, electrical energy, magnetic energy, gravitational energy and chemical energy etc. All energy is basically categorized into two classes known as kinetic energy and potential energy. There are differences between the two which can be beautifully illustrated with the help of an example.

Suppose you have a rubber ball in you hand and throw it up in the air. The ball initially has zero potential energy as it is close to earth and static. But it gains kinetic energy as its speed increases. This kinetic energy slowly decreases because of the gravitational pull of the earth and finally it becomes zero when the ball stops in mid air. At its highest point in the motion, the ball only has potential energy by virtue of its height and the state of rest. Now the ball again starts its downward journey and its kinetic energy again starts to increase while its potential energy decreases as it comes back to the ground. Finally when it reaches the ground, it has the highest kinetic energy while its potential energy has become zero.

A waterfall has both potential energy as well as kinetic energy by virtue of its height. When water is at the top of a waterfall, it is full of potential energy. But when water touches the bottom, it has only kinetic energy and no potential energy. This kinetic energy is used to generate electricity by converting kinetic energy into electrical energy. When you play with yo-yo, the ball has only potential energy when it touches your hand, but it gains kinetic energy when it goes down and at the lowest point all its potential energy has been transformed into kinetic energy. When the ball goes up again, its kinetic energy is again transformed into potential energy.

It is clear from the above example that kinetic energy is the energy an object possesses because of its state of motion. In fact, the word kinetic has its origins in the Greek word Kinesis which means motion.

Potential energy on the other hand is the energy an object possesses because of its virtue of rest. It is also known as restoring energy. All objects have a tendency to return to their position of rest as potential energy works against any displacement force. This is because of the gravitational force of the earth. Had there been no gravitational force, a ball thrown up in in air would never come back to earth and continue its upward journey.

Energy cannot be created or destroyed. It only changes its forms which is why kinetic energy is converted into potential energy and vice versa.

 Summary • All forms of energy are basically categorized in to two classes known as kinetic energy and potential energy. • Kinetic energy is the energy an object possesses because of its state of motion, while potential energy is because of its position of rest. • Both KE and PE keep transforming into one another all the time.

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