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

Step-by-step solution

Before the string is cut, tension is acting in the string in downward position. k x = T + 3 m g ......(i) T = m g ......(ii) ⇒           k x = 4 m g After the string is cut, T = 0 a = k x - 3 m g 3 m a = 4m g - 3 m g 3 m Acceleration of A is a = g 3 ↑ and acceleration of B is a = mg m = g ↓ .