10 Two particles of masses `m_(1)` and `m_(2)` initially at rest start moving towards each other under their mutual force of attraction. The speed of the centre of mass at any time t, when they are at a distance r apart, is

Two masses M_1 and M_2 separated by distance r start moving towards each other due to their own force of attraction. What will be the change in centre of mass?

Two bodies of masses m_1 and m_2 initially at rest at infinite distance apart move towards each other under gravitational force of attraction. Their relative velocity of approach when they are separated by a distance r is (G= universal gravitational constant.)

Two particles P and Q of mass 1 kg and 3 kg respectively start moving towards each other form rest under mutual attraction. What is the velocity of their center of mass ?

Two particle A and B (both initially at rest) start moving towards each other under 3 mutual force of attraction. At the instant when the speed of a is v and the speed of B is 2v, the speed of the centre of mass is

Two particles A and B (both initially at rest ) start moving towards each other under a mutual force of attraction. At the instant when the speed of A is v and the speed of B is 2v, the speed of the centre of mass is