A ring of mass m=0.3kg can slide freely on smooth vertical rod. A light and inextensible string is connected to the ring and passes over a smooth and fixed pulley as shown in the figure. The distance of the pulley from the rod is 0.8m and the other end of the string is connected to a block of mass M=0.5kg . The ring is held in level with pulley and then released from rest. Determine the distance (in meter) by which the ring moves down before coming to rest for the first time.