Explain the following:
(a) An object increases its energy when raised through a height.
(b) Energy is neither created nor destroyed then from where do we get energy.
(c) When we push thewall, the wall does not move and no work is done

(a)
Potential energy = m g h
As height increases, the potential energy also increases

(b)
From the law of conservation of energy, it can be concluded that energy neither be created nor destroyed.
Hence, we get energy only from the conversion from one state to another.

Example: When a stone is dropped, its potential energy changes to kinetic energy.

(c)

Work done = Force x Displacement
As there is no movement of the wall, the displacement of the wall is equal to zero.
Hence, the work done is also equal to zero.