Question

How to prove law of conservative force is gravitational force

Answer 1

Basically all forces that are produced by a field such as electic field, magnetic field ,gravitational field etc are conservative forces. You cannot argue why is the work done by theforce is zero in a conservative force or rather gravitational force, because it is observed and is a law(newton 's law ofgravitation).

Answer 2

$\textbf{Answer is in attachment!}$