The ends of string are attached to two blocks of masses 5 kg and 3 kg as shown in figure. The 5 kg block rests on horizontal surface and the three kg block which is vertically above it is in equilibrium with the spring compressed by 1 cm. 3 kg block is post down for that by 1 cm and released. Find the minimum value of x so that the 5 kg block maybe left of ground during the subsequent motion.