Block A of mass M = 2 kg is connected to another block B of mass m= 1 kg with a string and a spring of force constant k = 600 N//m as shown in Fig. Initially, spring is compressed to 10 cm and whole system is moving on a smooth surface with a velocity v = 1 m//s. At any time, thread is burnt, the velocity of block A, when B is having maximum velocity w.r.t. ground, is

Block A of mass M = 2 kg is connected to another block B of mass m= 1

1.	Block A of mass M = 2 kg is connected to another block B of mass m= 1 kg with a string and a spring of force constant k = 600 N//m as shown in Fig. Initially, spring is compressed to 10 cm and whole system is moving on a smooth surface with a velocity v = 1 m//s. At any time, thread is burnt, the velocity of block A, when B is having maximum velocity w.r.t. ground, is
Answer» zero `1m//S` `3m//s` none of these SOLUTION :The velocity of `B` will be maximum when spring comes to its natural LENGTH. Let at the at time their velocities are `v_(1)` and `v_(2)` as SHOWN CONSERVATION of momentum, `2v_(1)+1v_(2)(2+1)xx1implies2v_(1)+v_(2)=3`…..i Conservation of energy `1/22v_(1)^(2)+1/21v_(2)^(2)=1/2600(10/100)^(2)=1/23(1)^(2)implies2v_(1)^(2)+v_(2)^(2)=9` From EQN i and ii `v_(1)=2m//s, v_(2)=-1m//s` or `v_(1)=0, v_(2)=3m//s` The second solution is possible.