Two blocks A and B having masses m1 1 = kg and m2 = 4 kg are arranged as shown in Figure. The pulleys P and Q are light and frictionless. All blocks are resting on the horizontal floor and pulleys are held such that strings remain just taut. At moment t=0, a force F=30N starts acting on the pulley P along vertically upward direction as shown in the Figure: Determine
(a) The time when blocks A and B lose contact with ground,
(b) The velocity of A when B loses contact with ground,
(c) The height raised by A till this instant.