Question

A sphere S rolls without slipping, moving with a constant speed on a plank P. The friction between the upper surface of P and the sphere is sufficient to prevent slipping, while the lower surface of P is smooth and rests on the ground. Initially, P is fixed to the ground by a pin N. If N is suddenly removed:

• A. S will begir to slip on P
• B. P will begin to move backwards
• C. The speed of S will decrease and its angular velocity will increase
• D. There will be no change in the motion of S and P will not be at rest.

Answer 1

The correct option is D There will be no change in the motion of S and P will not be at rest.

In pure rolling, the frictional force will be zero. So not any change occur $S$ will rotate as it is.