A ball of mass 3 kg and a ball of mass 2 kg roll towards each other on a flat surface. How far is the centre of mass from the 3 kg ball of the 2 balls are separated by 6 m?

2.4 m 4.8 m 3.6 m 1.2 m

2.4 m

Sum of masses = 3 + 2 = 5 kg Centre of mass from 3 kg ball = (6 x 2) / 5     = 2.4 m.