Two blocks A and B of masses 3 m 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 :

Question

Two blocks A and B of masses 3 m 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) (g/3) , g  (B) g , g  (C)  (g/3) , (g/3)  (D) g , (g/3)

Tardigrade Admin · Accepted Answer

Before the string is cut k x=T+3 m g...(1) T=m g...(2)

⇒ k x=4 m g After the string is cut, T=0 a=(k x-3 m g/3 m) a=(4 m g-3 m g/3 m) a=(g/3) uparrow

Q. Two blocks $A$ and $B$ of masses $3 m$ 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 :

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

$g, g$

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

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

Before the string is cut
$k x = T + 3 m g$ ...(1)
$T = m g$ ...(2)

$\Rightarrow k x = 4 m g$
After the string is cut, $T = 0$
$a = \frac{k x - 3 m g}{3 m}$
$a = \frac{4 m g - 3 m g}{3 m}$
$a = \frac{g}{3} ↑$

Q. 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 :

3g​,g

g,g

3g​,3g​

g,3g​