(b) Two balls X and Y, of equal diameter but different masses 0.24kg and 0.12kg respectively, slide towards each other on a frictionless horizontal surface, as shown in [Fig. 2.1]. Both balls have initial speed 2.3ms⁻¹ before they collide with each other. [Fig. 2.2] shows the variation with time t of the force Fy exerted on ball Y by ball X during the collision.