Question

two blocks A&B of mass m& 2m one is connected to string and one. is to spring find acceleration of both blocks just after release​

Answer 1

g g

__ ⬇️ __⬆️

3 3

↑Let us assume that the block A of mass m is tied to the spring. However at t=0s, the spring is not compressed or extended.

Let T be the tension in the string going over pulley.   Just after releasing the force on block A, both blocks move with the same acceleration. The tension is same in the rope on both sides.  The equations of motion for both blocks are: 

 T−mg=ma

2mg−T=2ma

So  mg=3ma=>a=g/3

So at t = 0, block A moves up initially with an acceleration g/3 and block B moves down with accelerationg/3.