JEE Main2013PhysicsGravitationActual
What is the minimum energy required to launch a satellite of mass m from the surface of a planet of mass M and radius R in a circular orbit at an altitude of 2R ?
Options
- AGmM 2 R
- BGmM 3 R
- C5 GmM 6 R
- D2 GmM 3 R
Correct answer
C. 5 GmM 6 R
Step-by-step solution
As we know, Gravitational potential cnergy = - GMm r and orbital velocity, v 0 = GM / R + h E f = 1 2 mv 0 2 - GMm 3 R = 1 2   m GM 3 R - GMm 3 R = GMm 3 R 1 2 - 1 = - GMm 6 R E i = - GMm R + K E i = E f Therefore minimum required energy, K = 5 GMm 6 R