Question

If satellite of mass 400 kg revolves around the earth in an orbit with speed 200 m/s then its potential energy is

• A. -1.2 MJ
• B. -8.0 MJ
• C. -16 MJ
• D. -2.4 MJ

Answer 1

The correct option is C -16 MJ

$\begin{array}{c}\frac{m{v}^2}{R}=-\frac{GMm}{R^2}\\ \Rightarrow \frac{400\times 200\times 200}{R}=\frac{GMm}{R^2}\\ \Rightarrow -\frac{GMm}{R^2}=-400\times 200\times 200\\ =-16\times {10}^{6}J\\ =-16MJ\end{array}$

$\therefore$ Option $C$ is correct.