Two objectes of mass m and 4m are at rest at and infinite seperation. They move towards each other under mutual gravitational attraction. If G is the universal gravitational constant. Then at seperation r

Options

A. The total energy of the two objects is zero
B. Net angular momentum of both the objects is zero about any point
C. The total kinetic energy of the objects is `(4Gm^2)//r`
D. Their relative velocity of approach is `((8Gm)/r)^(1//2)`

Answer

A, B, C

Explanation

The objects of masses m and 4m are rest at an infinity separation. They move towards each other under mutual gravitational attraction. If G is the universal gravitational constant at separation r, then the total energy of the two objects is zero and also the net angular momentum of both the objects is zero about any point, also the total kinetic energy of the objects is `4Gm^2//r`