Question

A body weighs $700N$ on the surface of the earth. What is its weight on the surface of a planet, whose mass is $1/7$th and radius is $1/2$ as that of the earth?

• A. $400N$
• B. $300N$
• C. $700N$
• D. $500N$

Answer 1

The correct option is A $400N$

$F=\frac{GMm}{R^2}=700N$

If $M\to \frac{M}{7}R\to \frac{R}{2}\therefore F^1=\frac{GMm.4}{7R^2}=\frac{4}{7}F=\frac{4}{7}\ast 700N=400N$