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 $\frac{g}{3},g$

Before cutting the string
Therefore, $T=mg$
After cutting the string,
$a_A=\frac{4mg-3mg}{3m}=\frac{g}{3}$
$a_B=\frac{mg}{m}=g$