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#### Published on 24 Mar 2015 | over 2 years ago

You will learn about "Potential and Kinetic Energy" in this video. The law of conservation of energy states that energy cannot be created or destroyed, it can only be converted from one form to another.

Potential energy is energy due to position while kinetic energy is energy due to motion. The unit of energy is joules.

To understand this better, let us take an example. Look at this pendulum. When we hold it on one side, at that time, it has a certain amount of potential energy. When the pendulum is released, this potential energy starts getting converted to kinetic energy. As the pendulum moves back and forth, the kinetic energy is converted to potential energy and vice versa until the pendulum stops.

The formula for potential energy is mgh, where m = mass, g = acceleration due to gravity and h = height. If we climb on top of a tree, the potential energy possessed by us will be mgh. Here, if we assume mass = 30 kg, acceleration due to gravity = 9.8 m/s^2 and height of the tree as 20 metres, then the potential energy would be 30 * 9.8 * 20 = 5880 joules.

At the top, the K.E. is zero. If we jump, then the stored potential energy starts getting converted to kinetic energy. Just before we land, all of the potential energy gets converted to kinetic energy. Now, the potential energy = 0. The kinetic energy can be calculated using the formula, 1/2mv^2 where m = mass and v = velocity.

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