6 Two particles of masses 1.3 kg and 0.7 kg are connected by a light inextensible string that passes over a fixed smooth pulley. The particles are held at the same vertical height with the string taut. The distance of each particle above a horizontal plane is 2 m , and the distance of each particle below the pulley is 4 m . The particles are released from rest.

1. Find
   (a) the tension in the string before the particle of mass 1.3 kg reaches the plane,
   (b) the time taken for the particle of mass 1.3 kg to reach the plane.
2. Find the greatest height of the particle of mass 0.7 kg above the plane.