What is the minimum energy required to launch a satellite of mass m from the surface of a planet of mass M…

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 ?
  1. GmM 2 R
  2. GmM 3 R
  3. 5 GmM 6 R
  4. 2 GmM 3 R

Solution

As we know,
Gravitational potential cnergy =-GMmr
and orbital velocity, v0=GM/R+h
Ef=12mv02-GMm3R=12 mGM3R-GMm3R
=GMm3R12-1=-GMm6R
Ei=-GMmR+K
Ei=Ef
Therefore minimum required energy,
K=5GMm6R

Asked in: JEE Main 2013 (07 Apr)

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