(N/A) Potential energy is the energy possessed by a body by virtue of its position or configuration. If the configuration of the system changes,its potential energy changes.
Gravitational potential energy is the energy stored in an object due to its position in a gravitational field. When an object of mass $m$ is lifted to a height $h$ above the Earth's surface,the work done against the gravitational force is stored as gravitational potential energy.
The work done by an external force $F$ is given by $W = F d \cos \theta$.
Here,$F = mg$,$d = h$,and $\theta = 0^{\circ}$ (since the force and displacement are in the same upward direction).
Therefore,$W = (mg)(h) \cos 0^{\circ} = mgh$.
This work is stored as gravitational potential energy,$U = mgh$.
The dimensional formula for energy is derived from $U = mgh$:
$[M] \times [LT^{-2}] \times [L] = [M^{1} L^{2} T^{-2}]$.
The $SI$ unit of gravitational potential energy is Joule $(J)$.