Question

A body falls freely under gravity from the terrace of a building. Its kinetic energy is 75 J when it hits the ground. i) How much was the potential energy at the start of its fall? ii) At a certain point of its fall, if the potential energy is 36 J, how much is kinetic energy? ​

Answer 1

Potential energy is energy stored in an object. This energy has the potential to do work. Gravity gives potential energy to an object. This potential energy is a result of gravity pulling downwards. The gravitational constant, g, is the acceleration of an object due to gravity. This acceleration is about 10 meters per second on earth. The formula for potential energy due to gravity is PE = mgh. As the object gets closer to the ground, its potential energy decreases while its kinetic energy increases. 

In this case, a body of mass 5 kg kept at a height of 10 m. So the potential energy is given as 5 * 10 *10 = 500 J.

Hence, the potential energy of a body of mass 5 kg kept at a height of 10 m is 500 J.