A block of mass M1 = 10 kg is placed on a slab of mass M2 =30kg, The slab lies on a frictionless horizontal surface as shown in fig. The coefficient of staticfriction between the block and slab is µ1 =0.5 and that of dynamic friction is µ2 =0.15.A force F =40N acts on block M1. What will be the acceleration with which the slab will move?  (Take g=10m/s2 )

The slab will move due to the force exerted on it due to the friction between the block and slab. When the force acting on the block is less than the static friction, it will not move. The total force causing acceleration of M1 and M2 both will be the force applied.Limiting friction =μM1g=0⋅5×10×10=50NSo, the applied force will not cause motion of M1.∴The acceleration of system a=40N(10+30)kg=1m/s2