Three particles \(P\), \(Q\) and \(R\), of masses 0.1 kg, 0.2 kg and 0.5 kg respectively, are at rest in a straight line on a smooth horizontal plane. Particle \(P\) is projected towards \(Q\) at a speed of \(5 \text{ m s}^{-1}\). After \(P\) and \(Q\) collide, \(P\) rebounds with speed \(1 \text{ m s}^{-1}\).
- Find the speed of \(Q\) immediately after the collision with \(P\). [3]
\(Q\) now collides with \(R\). Immediately after the collision with \(Q\), \(R\) begins to move with speed \(V \text{ m s}^{-1}\).
- Given that there is no subsequent collision between \(P\) and \(Q\), find the greatest possible value of \(V\). [3]