Question

Explain by an example what is meant by potential energy. Write down the expression for gravitational potential energy of a body of mass m placed at a height h above the surface of the earth.

Answer 1

An example to explain the fundamental meaning of potential energy is as follows:
A brick lying on the ground has no energy, so it cannot do any work. If we lift the brick to the roof of a house, the work done in lifting the brick against gravity gets stored in it in the form of potential energy. Thus, the energy in the brick is due to its higher position with respect to the ground, which is known as potential energy.

We can calculate the potential energy of a body of mass (m) lifted by a height (h) as,
Potential energy = (Weight of body) × (Vertical distance)
So,
P.E = m × g × h
Where,
(P.E) - Potential energy
(m) - Mass of body
(g) - Acceleration due to gravity
(h) - Height by which the body is lifted