Question

The system of two weights 1 & 2 with masses $M_1$ and $M_2$ are connected with weightless spring as shown. The system is resting on the support 'S'. Find the acceleration of each of the weights just after the support 'S' is quickly removed.

• A. = =
• B.
• C.
• D.

Answer 1

The correct option is D

Force of spring does not change instantaneously so find spring force at initial instant

Initial instant

Initially $M_1$g = kx
When support is removed spring force does not change

For $M_1$ : $M_1$g - kx = $M_1$$a_1$ or $a_1$ = 0 as kx = $M_1$g

For $M_2$ : $M_2$g + kx = $M_2$$a_2$ or $a_2$ = $\frac{(M_1+M_2)g}{M_2}$