Question

A satellite moves around the earth in a circular orbit with speed $V$. If $m$ is mass of the satellite then its total energy is

• A. $\frac{1}{2}m{V}^2$
• B. $m{V}^2$
• C. $-\frac{1}{2}m{V}^2$
• D. $\frac{3}{2}m{V}^2$

Answer 1

The correct option is C $-\frac{1}{2}m{V}^2$

Total energy $=$ Kinetic energy $+$ Potential energy

$KE=\frac{GMm}{2r}$
$PE=-\frac{GMm}{r}$
$TE=-\frac{GMm}{2r}=-KE=-\frac{1}{2}m{V}^2$