Bearings Reduce Friction. Bearings are constrained elements used to reduce the friction of certain moving parts in a machine or device. This is done by replacing sliding friction with rolling friction. Bearings are used to provide better linear motion or rotation around a fixed axis.
Ball bearings are used in machines which have lot of movement in their working process. Ball bearings reduce the friction during motion, so that efficiency of the machines is increased, and they move in a smooth manner.