question_answer

Energy required to move a body of mass m from an orbit of radius 2 R to 3 R is                      [AIEEE 2002]

A)  \[GMm/12{{R}^{2}}\]

B)       \[GMm/3{{R}^{2}}\]

C)  \[GMm/8R\]     

D)       \[GMm/6R\]

Correct Answer: D

Solution :

Gravitational potential energy of body will be

where,    mass of the earth,

mass of the body,

radius of the earth.

At ,

At ,

Energy required to move a body of mass m from an orbit of radius 2 R to 3R is