Question

What are the conditions for pure rolling?

Answer 1

We are asked to list out the conditions for pure rolling. We can start to attempt this question by stating the types of motion possible and defining them. We can then move onto stating the conditions for each one to happen where we will find the solution to our question as well.

Complete answer:
Rolling motion is the one which is a combination of both rotational and linear motion. This type of motion (rolling) can be classified into two, pure rolling and impure rolling.

Pure rolling: This type of rolling motion is the one in which sliding motion is absent.That is, the body rolls on the surface without sliding.
Impure rolling: In this kind of rolling motion, the body in motion rolls as well as slides on the surface.

Pure rolling occurs when there is no resistance against the motion. Friction is necessary to start the rolling of the ball but once it starts rolling, it really doesn’t require friction. Pure rolling is a case when the point of lowest contact of the rolling body with ground remains at rest and the body is deliberated to be rotating about this point of contact.

Note: Purely rotational motion or rolling without slipping occurs if every particle in the body moves in a rotational motion about a single line or along the centre of mass. This line about which all the particles in a body moves is called the axis of rotation. For pure rolling motion linear velocity is equal to angular velocity. During pure rolling work done due fractional force will always be zero.