Explain why friction is necessary to make the disc in Fig. 7.41 roll in the direction indicated. (a) Give the direction of frictional force at B, and the sense of frictional torque, before perfect rolling begins. (b) What is the force of friction after perfect rolling begins?

What is the direction of force of friction acting on a moving object?

When a wheel is rolling on a level road, what'is the direction of frictional force between the wheel and the road?

Read each statement below carefully, and state, with reasons, if it is true, or false, During rolling, the force of friction acts in the same direction as the direction of motion of the CM of the body.

A disc rotating about its axis with angular speed ?Qis placed lightly (without any translational push) on 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?