Q. The escape velocity of an object on a planet whose $g$ value is 9 times on earth and whose radius is 4 times that of earth in $km/s$ is
A) 67.2
B) 33.6
C) 16.8
D) 25.2
Explanation
(a) $\frac{v_{p}}{v_{e}} = \sqrt{\frac{g_{p}}{g_{e}} \times \frac{R_{p}}{R_{e}}} = \sqrt{9 \times 4} = 6\ \therefore v_{p} = 6 \times v_{e} = 67.2km/s$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.