Question

Derive an expression for the various of acceleration due to gravity with height 'h' from the surface of earth?

Answer 1

let us consider a man on earth surface
then he experiences gravitation of force
GMm/R^2
if he fly like a bird he experiences same force as like a ground
when he dig a mine and went inside
he experience
GMm/(R-h)^2
since h is like a ant towards elephant R
(R-h)^2~=(R-2h)

F=GMm(R-2h)