What is rolling friction ? Write laws of rolling friction. Define coefficient of rolling friction.

Explanation

When body is rolling without sliding friction force is called rolling friction it is denoted by `f_(r )`
During rolling the surface in contact get momentarily deformed a little and small part of body remain in contact with surface
As a result there is component of the contact force parallel to surface which opposes motion
`mu_(f ) lt mu_(k) gt mu_(s)`