Moving parts in machinery involve relative sliding or rolling motion. Examples
of relative motion are linear sliding motion, such as in machine tools, and rotation
motion, such as in motor vehicle wheels. Most bearings are used to support
rotating shafts in machines. Rubbing of two bodies that are loaded by a normal
force (in the direction normal to the contact area) generates energy losses by
friction and wear. Appropriate bearing design can minimize friction and wear as
well as early failure of machinery...