A person normally weighing 50 kg stands, a body of mass m is attached to one end of a massless spring which is suspended vertically from a fixed point. The mass is held in hand, so that the spring is neighter stretched nor comprssed. Suddenly the support of the hand is removed. The lawest position attained by the mass during oscillation is 4 cm below the point, where it was held in hand. What is the amplitude of oscillation?