Find the relation between acceleration of 1 and 2.

Explanation

At any instant of time let `x_(1)` and `x_(2)` be the displacements of
1 and 2 from a fixed line. Then `x_(1)+x_(2)`=constant
Differentiating w.r.t. time, `v_(1)+v_(2)=0`
Again differentiating w.r.t. time `a_(1)+a_(2)=0rArra_(1)=-a_(2)`
So acceleration of 1 and 2 are equal but in opposite directions.