Small smooth spheres A and B, of equal radii and of masses 6 kg and 2 kg respectively, lie on a smooth horizontal plane. Initially A is moving towards B with speed 5 m s^-1 and B is moving towards A with speed 3 m s^-1. After the spheres collide, both A and B move in the same direction and the difference in the speeds of the spheres is 2 m s^-1.

Find the loss of kinetic energy of the system due to the collision.