Consider two satellites A and B of equal mass m, moving in same circular orbit about earth, but in opposite sense as shown in figure. The orbital radius is r. The satellites undergo a collision which is perfectly inelastic. From this situation, mark out the correct statement(s). [Take mass of earth as M, Neglect gravitational interaction between the planets]

Just before collision, the total energy of two satellites is,

$E=-\frac{GMm}{2r}-\frac{GMm}{2r}-\frac{GMm}{r}$

Let orbital velocity is $v_1$ then from momentum conservation.

$mv-mv=2m\times v_1$$\Rightarrow v_1=0$             

As velocity of combined mass just after collision is zero, the combined mass will fall rowards earth. At this instant, the total energy of the system only consist of the gravitational potential energy given by 

$U=\frac{GM\times 2m}{2r}$