Question

A point mass $m$ is placed at the centre of a thin spherical shell of mass $m$ and radius $R$. Then the total crushing force experienced by the shell is:

• A. $\frac{3G{m}^2}{8R^2}$
• B. $\frac{G{m}^2}{8R^2}$
• C. $\frac{-3G{m}^2}{R}$
• D. $\frac{5G{m}^2}{8R^2}$

Answer 1

The correct option is C $\frac{-3G{m}^2}{R}$

The potential at the surface of the shell is equal to the sum of Potential due to particle and the Potential due to shell

$\frac{-Gm}{R}+-\frac{2Gm}{R}=\frac{-3Gm}{R}$