Question

Explain the energy transformation taking place in a freely falling body.

Answer 1

1. According to the law of conservation of energy, 'energy can neither be created nor be destroyed but it gets converted from one form to another form.'
2. The process in which energy changes from one form to another form is known as energy transformation.
3. Suppose a stone is dropped from the roof, say point X (see figure).
4. At point X, the total mechanical energy of the stone is due to its potential energy (as the stone is at rest).
5. Now as the stone starts falling down, its height keeps on decreasing, resulting in a decrease in its potential energy.
6. But now as the stone is in motion, it has acquired kinetic energy.
7. Therefore, as the stone keeps falling down, its potential energy decreases and kinetic energy increases by an equal amount, keeping the total mechanical energy constant at any in-between point Y.
8. Just before touching the ground, i.e. at point Z, the entire mechanical energy of the stone is kinetic energy and its potential energy is zero.
9. The total mechanical energy of the stone is still constant and is equal to what it was at the starting point X and at intermediate point Y.