A body weighs 72 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 ?

Options

A. 32 N
B. 30 N
C. 24 N
D. 48 N

Answer

A

Explanation

`w_(s) = mg_(s) = 72 N `
`w_(h) = mg_(h) = (mg_(s))/((1 + (h)/(R))^(2)) = (72 N)/((1 + (R//2)/(R))^(2)) = (72)/(9//4)`
`w_(h) = 32 N`