M1 June 2007 Q2

2. Two particles \(A\) and \(B\), of mass 0.3 kg and \(m\) kg respectively, are moving in opposite directions along the same straight horizontal line so that the particles collide directly. Immediately before the collision, the speeds of \(A\) and \(B\) are 8 m s\(^{-1}\) and 4 m s\(^{-1}\) respectively. In the collision the direction of motion of each particle is reversed and, immediately after the collision, the speed of each particle is 2 m s\(^{-1}\). Find