Question

Two blocks $A$ and $B$ of masses $3m$ and $m$ respectively are connected by a massless and inextensible string. The whole system is suspended by a massless spring as shown in figure. The magnitudes of acceleration of $A$ and $B$ immediately after the string is cut, are respectively:

• A. $\frac{g}{3},\frac{g}{3}$
• B. $g,\frac{g}{3}$
• C. $\frac{g}{3},g$
• D. $g,g$

Answer 1

The correct option is C $\frac{g}{3},g$

Here block $B$ free falls thus acceleration of block $B$ is $g$

Force change for block

$A$ is $mg$

thus $mg=3ma$

$a=g/3$

Hence acceleration of

block $A$ is $g/3$

Correct option is $\left(C\right)$