Question

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

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

Answer 1

The Correct Option is B

$w_{s}=mg_{s}=72\,N$ $w_{h}=mg_{h}=\frac{mg_{s}}{\left(1+\frac{h}{R}\right)^{2}}$ $=\frac{72\,N}{\left(1+\frac{R /2}{2}\right)}$ $=\frac{72}{9 /4}$ $w_{h}=32\,N$