Q. A body weighs $700\ g\ wt$ on the surface of the earth. How much will it weigh on the surface of a planet whose mass is $\frac{1}{7}$ and radius is half that of the earth
A) $200\ g\ wt$
B) $400\ g\ wt$
C) $50\ g\ wt$
D) $300\ g\ wt$
Explanation
(b) We know that $g = \frac{GM}{R^{2}}$
On the planet $g_{p} = \frac{GM/7}{R^{2}/4} = \frac{4}{7}g$
Hence weight on the planet $= 700 \times \frac{4}{7} = 400\ gm\ wt$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.