Explain why friction is necessary to make the disc roll in the direction indicated.
Given the direction of friction force at B, and the sense of frictional torque, before perfect rolling begins.

A disc spinning clockwise about its axis with angular velocity omega_0 is set on a rough horizontal plane[Fig.]. What si the direction of frictional force at point P and sense of frictional torque ,before pure rolling starts? .

In which direction the force of friction acts?

Supose your writing desk is tilted a little. A book kept on it starts sliding down. Show the direction of frictional force acting on it.

Suppose your writing desk is tiltrd a little .A book kept on it starts sliding down. Show the direction of frictional force acting on it.

A disc rotating about its axis with angular speed omega_0 is placed lightly (without any translational push) 011 a perfectly frictionless table. The radius of the disc is R. What are the linear velocities of the points A, B and C on the disc shown in Fig. 7.41? Will the disc roll in the direction indicated ?