A body weighs 72 N on the surface of the earth. What is the gravitational force on it due to earth at a height equal to half the radius of the earth from the surface

Options

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

Answer

B

Explanation

`W_s=mg_s=72N`
`W_h=mg_h=(mg_s)/((1+h/R)^2)=(72N)/((1+(R//2)/R)^2)=72/(9//4)`
`W_h=32N`