Two blocks of mass 2kg are connected by a massless ideal spring of spring constant K = 10N/m. The upper block is suspended from roof by a light string A. The system shown is in equilibrium. The string A is now cut, the acceleration of upper block just after the string A is cut will be (g = 10m/s2)
(A) 0m/s2
(B) 10m/s2
(C) 15m/s2
(D) 20m/s2
