# Block  of mass  =2 kg is connected to another block of mass  kg with a string and a spring of force constant  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  =1m/s. At any time,thread is burnt, the velocity of block ,when  is having maximum velocity w.r.t. ground,is a) Zero b) 1 m/s c) 3m/s d) None of these

## Question ID - 100032 | SaraNextGen Answer Block  of mass  =2 kg is connected to another block of mass  kg with a string and a spring of force constant  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  =1m/s. At any time,thread is burnt, the velocity of block ,when  is having maximum velocity w.r.t. ground,is a) Zero b) 1 m/s c) 3m/s d) None of these

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Answer Key : (c) -

(c)

The velocity of  will be maximum when spring comes to its natural length.Let at that time their velocities are and  as shown

Conservation of momentum:

(i)

Conservation of energy:

(ii)

From Eqs. (i) and (ii),

m/s,  or

The second solution is possible