(mechanical engineering) the force required to move two sliding surfaces over each other, divided by the force holding them together. It is reduced once the motion has started
coefficient of friction
A measure of the amount of resistance that a surface exerts on or substances moving over it, equal to the ratio between the maximal frictional force that the surface exerts and the force pushing the object toward the surface. The coefficient of friction is not always the same for objects that are motionless and objects that are in motion; motionless objects often experience more friction than moving ones, requiring more force to put them in motion than to sustain them in motion. ◇ The static coefficient of friction is the coefficient of friction that applies to objects that are motionless. ◇ The kinetic or sliding coefficient of friction is the coefficient of friction that applies to objects that are in motion. See also drag, friction.
noun, Thermodynamics. 1. a constant that denotes the efficiency of a refrigerator, expressed as the amount of heat removed from a substance being refrigerated divided by the amount of work necessary to remove the heat. Abbreviation: COP.
noun, Physics. 1. the ratio of the relative velocity after impact to the relative velocity before the impact of two colliding bodies, equal to 1 for an elastic collision and 0 for an inelastic collision.
- Coefficient of variation
noun 1. (statistics) a measure of the relative variation of distribution independent of the units of measurement; the standard deviation divided by the mean, sometimes expressed as a percentage noun a statistical measure of investment risk in which risk is defined as the standard deviation per unit of expected return; the ratio of standard deviation […]
noun, Physics. 1. the measure of the viscosity of a fluid, equal to the force per unit area required to maintain a difference of velocity of one unit distance per unit time between two parallel planes in the fluid that lie in the direction of flow and are separated by one unit distance: usually expressed […]