Two block of mass `2kg` are connected by a massless ideal spring of spring contant `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//s^(2)` .

Options

A. `0 m//s^(2)`
B. `10 m//s^(2)`
C. `15 m//s^(2)`
D. `20 m//s^(2)`

Answer

D