# A sphere S rolls without slipping, moving with 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 rest on the ground. Initially P is fixed to the ground by a pin N. If N is suddenly removed :

$\begin{array}{1 1}(a)\;\text{S will begin to slip on P}\\(b)\;\text{P will begin to move back wards}\\(c)\;\text{the speed of s will decrease, and its angular velocity will increase}\\(d)\;\text{there will be no charge in the motion of S and P will still be at rest }\end{array}$

In the absence of other forces, friction will not act when the body is having a pure rolling motion.
(D) there will be no charge in the motion of S and P will still be at rest is the right answer.
edited Apr 2, 2014