Question

A body weighs 700 gm 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 gm w
• B. 400 gm wt
• C. 50 gm wt
• D. 300 gm wt

Answer 1

Answer: (B)

400 gm wt

Answer 2

We know that $g = \frac { G M } { R ^ { 2 } }$

On the planet $g _ { p } = \frac { G M / 7 } { R ^ { 2 } / 4 } = \frac { 4 g } { 7 } = \frac { 4 } { 7 } g$

Hence weight on the planet