Question

the radius of the earth is 6400 km and a body in its surface weights 40N. The weight on the same body at a height of 6400km from the surface of earth is

Answer 1

Acceleration due to gravity at a height of 6400 km is
g’ = g[R / (R + h)]²

Multiply both sides by “m”
mg’ = mg[R / (R + h)]²
= 40 N × [6400 km / (6400 km + 6400 km)]²
= 40 N × 1/4
= 10 N

∴ Weight at that height is 10 N.