51. A balloon starts rising from the ground, vertically upwards, uniformly at the rate of 1 m s-1. At the end of 4 seconds, a body is released from the balloon. Calculate the time taken by the released body to reach the ground. 51. A balloon starts rising from the ground , vertically upwards , uniformly at the rate of 1 m s - 1 . At the end of 4 seconds , a body is released from the balloon . Calculate the time taken by the released body to reach the ground