The Friction Force, Ffriction
Friction—Complex and Simplified
Friction occurs between all matter in contact. Any combination of two materials, whether gaseous, liquid, or solid, will have unique friction characteristics dependent on many factors: the materials themselves, their surface finish, their speed relative to each other; the presence of any lubricant or impurities (dust and dirt); the direction of movement relative to any grain-like structure in a material; the pressure between the materials; temperature, and on and on. Because of all these factors, accurate mathematical models of frictional effects are extremely complex, and this is especially so for fluids. Fortunately, for the rough predictions of the loads imposed by friction on ...