Question

A body of weight 72 N moves from the surface of earth at a height half of the radius of earth, then gravitational force exerted on it will be

• A. 36 N
• B. 32 N
• C. 144 N
• D. 50 N

Answer 1

Answer: (B)

32 N

Answer 2

$F_{surface } = G \frac{Mm}{ {R_e}^2}$
$F_{R_c /2} = G \frac{ Mm}{ (R_e + R_e /2)^2} =\frac{4}{9} \times F_{surface } = \frac{4}{9}\times 72= 32\, N$.