A particle A A\,A of mass 5 kg rests on a smooth horizontal table. Particle A A\,A is attached to one end of a light inextensible string which passes over a smooth pulley fixed to the edge of the table. The other end of the string is attached to particle B B\,B of mass 4 kg which hangs freely below the pulley 1.4 m above the ground. The system is released from rest with the string taut. Particle A A\,A does not reach the pulley before B B\,B reaches the ground.

Find the tension in the string before B B\,B hits the ground.
Find the time taken by B B\,B to reach the ground.