JEE Advanced2013PhysicsGravitationActual
Two bodies, each of mass M , are kept fixed with a separation of 2 L . A particle of mass m is projected from the midpoint of the line joining their centers, perpendicular to the line. The gravitational constant is G . The correct statement (s) is (are) :
Options
- AThe minimum initial velocity of the mass m to escape the gravitational field of the two bodies is 4 G M L .
- BThe minimum initial velocity of the mass m to escape the gravitational field of the two bodies is 2 G M L .
- CThe minimum initial velocity of the mass m to escape the gravitational field of the two bodies is 2 G M L .
- DThe energy of the mass m remains constant.
Correct answer
B. The minimum initial velocity of the mass m to escape the gravitational field of the two bodies is 2 G M L .
Step-by-step solution
Applying mechanical energy conservation, U i + K E i = U f + K E f - G M m L × 2 + 1 2 m v 2 = 0 + 0 ⇒ v = 4 G M L ⇒ v =   2 G M L