Question

A body weighs 63 N on the surface of the earth. What is the gravitational force on it due to the earth at a height equal to half the radius of the earth?

Answer 1

Weight of the body = 63 N = mg 

Now at a certain height h, let the acceleration due to gravity be g_n. 

So, New weight = mg_n

We know that g_n = 

at a height of R_e/2

= g/(3/2)²

g_n = 4/9 g

New weight = mg_n= (mg) × 4/9

= 63 × 4/9

= 28 N.