Question

A cylinder of mass at and radius `R` rolls on a stationary plank of mass `M`. The lower surface of the plank is smooth and the upper surface is sufficiently rough with a coefficient of friction `mu`. A man is to hold the plank stationary with respect to the ground, as shown Fig.

The force exerted by the man to keep the plank stationary is equal to……

Answer 1

Zero. Since lowest point of the sphere is stationary wit respect to the plank, therefore friction force acting on te plank is zero. Thus, no force is required to keep the plank statiorary.