Friction

—This is defined by Rankine as “that force which acts between two bodies at their surface of contact so as to resist their sliding on each other, and which depends on the force with which the bodies are pre ed together. Morin’s laws of friction are as follows: (1) The friction between two bodies is directly proportional to the pre ure, that is, the coefficient is constant for all pre ures. (2) The ccefficient and amount of friction, pre ure being the same, is independent of the areas in contact. (3) The.ccefficient of friction is independent of velocity, although statie friction (friction at rest) is greater than the friction of motion.