Q. If the mass of earth is 80 times of that of a planet and diameter is double that of planet and $'g'$ on earth is $9.8m/s^{2}$, then the value of $'g'$ on that planet is
A) $4.9\ m/s^{2}$
B) $0.98\ m/s^{2}$
C) $0.49\ m/s^{2}$
D) $49\ m/s^{2}$
Explanation
(c) $g_{p} = g_{e}\left( \frac{M_{p}}{M_{e}} \right)\left( \frac{R_{e}}{R_{p}} \right)^{2} = 9.8\left( \frac{1}{80} \right)(2)^{2}$
$= 9.8/20 = 0.49m/s^{2}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.