Find out the acceleration of 2kg block in the figures shown at the instant 1kg block falls from 2kg block ( at t = 0 )

Explanation

F.B.D. is before fall of 1kg block

after the fall of the 1kg block tension will change instantaneously but spring force ( kx) doesn't change instantaneously F.B.D.s just after the fall of 1kg block

`a_(A) =( 30-20)/( 2)=5 m//s^(2)` ( upward ) `a_(B) =0m//s^(2)`