Q. An object weighs $72\ N$ on earth. Its weight at a height of $R/2$ from earth is
A) $32\ N$
B) $56\ N$
C) $72\ N$
D) Zero
Explanation
(a) $g^{'} = g\left( \frac{R}{R + h} \right)^{2} = g\left( \frac{R}{R + \frac{R}{2}} \right)^{2} = \frac{4}{9}g$
$\therefore W^{'} = \frac{4}{9} \times W = \frac{4}{9} \times 72 = 32N$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.