Q 11-07-017JEE MainEAMCET 2010 (Engineering)Medium
A launching vehicle carrying an artificial satellite of mass $m$ is set for launch on the surface of the earth of mass $M$ and radius $R$. If the satellite is intended to move in a circular orbit of radius $7R$, the minimum energy required to be spent by the launching vehicle on the satellite is
Answer: (B) $\dfrac{13GMm}{14R}$
Concept. Minimum energy $=$ orbital energy $-$ surface energy.
Step 1. Energies. $E_1 = -\dfrac{GMm}{R}$, $E_2 = -\dfrac{GMm}{14R}$.
Step 2. Difference. $\dfrac{13GMm}{14R}$.
Answer. $\dfrac{13GMm}{14R}$ (Option B).
Solution by Sreeraj P, M.Sc Physics