The expression of potential energy , i. e., P. E.=mgh , where the terms used have their usual meaning

Gravitational Potential energy:

The Gravitational potential energy of

an object at a point above the ground

is defined as the work done in raising

it from the ground to that point against

gravity.

Consider an object of mass "m" is raised

to heighth from the ground.

A force is required to do this. the

minimum force required to raise the

object is equal to the weight of the

object[mg]

The object gains energy equal to the

work done on it. Let the work done on

the object against gravity be "w"

WorkDone=W= Force x displacement

=mgxh

..W=mgh

since the workdone on the object is

equal to "mgh" an energy equal to "mgh"

units is gained by object.This is the

potential energy of object at height "h"

.. P.E=mgh