Question

Define potential energy. Derive an expression for gravitational potential energy. Mention its unit.

Answer 1

The energy possessed by a body due to its position or configuration is called potential energy.
Consider a body of mass $$‘m’$$ lying on the surface of the earth. Force required to lift the body is equal to its weight
$$\therefore F = mg$$
Let it be lifted through a height $$‘h’$$,
The work done on the body is $$W = FS$$
$$W = mgh (\because S = h)$$
This work done is stored in the body as its potential energy,
$$\therefore E_{p} = mgh$$
i.e. Gravitational potential energy $$= mgh$$
Its unit is Joule.