Q 11-07-029NEETJEE MainMedium
A satellite of mass $m$ is moved from a circular orbit of radius $2R$ to one of radius $4R$ around the Earth (mass $M$, radius $R$). The work required is
Answer: (A) $\dfrac{GMm}{8R}$
Total energy in orbit $r$: $E = -\dfrac{GMm}{2r}$.
$$W = E_2 - E_1 = -\frac{GMm}{8R} + \frac{GMm}{4R} = \frac{GMm}{8R}$$
Solution by Sreeraj P, M.Sc Physics