Derive the expression for gravitational potential energy.

Explanation

The gravitational potential due to mass `m_(1)` at a point P which is at a distance r from `m_(1)` is obtained by making `m_(2)` equal to unity (`m_(2)` = 1kg). Thus the gravitational potential V® due to mass `m_(1)` at a distance r is
`V(r)=-(Gm_1)/(r)`