Two blocks are resting on a floor as shown. There is no friction between floor and lower block (M=3 kg) but frictional coefficient between both blocks is 0.2. Both blocks move together with initial speed V towards the spring ,compresses it and due to force exerted by spring moves in reverse direction of initial motion. What is maximum value of V in (m/s), so that during motion there is no slipping between the blocks.

Question

 

a) 20 m/s b) 10 m/s c) 30 m/s d)40 m/s