JEE Advanced2011PhysicsGravitationActual
A satellite is moving with a constant speed v in a circular orbit about the earth. An object of mass m is ejected from the satellite such that it just escapes from the gravitational pull of the earth. At the time of its ejection, the kinetic energy of the object is
Options
- A1 2 m v^2
- Bm v^2
- C3 2 m v^2
- D2 m v^2
Correct answer
B. m v^2
Step-by-step solution
In circular orbit of a satellite, potential energy aligned & =-2 ( kinetic energy) & =-2 1 2 m v^2=-m v^2 aligned Just to escape from the gravitational pull, its total mechanical energy should be zero. Therefore, its kinetic energy should be +m v^2 . Correct answer is (b). Analysis of Question (i) Question is moderately difficult. (ii) In circular orbit of satellite U=- G M m r and K= G M m 2 r or U=-2 K Here, U is potential energy and K is kinetic energy.