Question

Why is rolling friction is better than slliding friction ?

Answer 1

Rolling friction is the resistance to motion experienced by a body when it rolls upon another. It is much less than sliding friction for same pair of bodies. When one body rolls upon another, there is theoretically no sliding or slip between them. And if both are perfectly rigid, there is no surface of contact.

Sliding friction is replaced in most machines by rolling friction by the use of ball bearings and it is very useful because rolling friction is smaller than sliding friction. In rolling surfaces, less area is in contact between the two bodies than sliding surfaces. Common examples are the use of ball bearings between the hubs and the axles of ceiling fans and bicycles .