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friction

(Encyclopedia)friction, resistance offered to the movement of one body past another body with which it is in contact. In certain situations friction is desired. Without friction the wheels of a locomotive could not...

bearing

(Encyclopedia)bearing, machine part designed to reduce friction between moving parts or to support moving loads. There are two main kinds of bearings: the antifriction type, such as the roller bearing and the ball ...

bursa, in anatomy

(Encyclopedia)bursa bûrˈsə [key], closed fibrous sac lined with a smooth membrane, producing a viscous lubricant known as synovial fluid. Bursas are found in regions where muscles or tendons rub against other mu...

match

(Encyclopedia)match, small stick whose chemically coated tip bursts into flame when struck on a rough surface. Before the introduction of the match, fire was made by friction methods using the stick and the groove,...

Coanda effect

(Encyclopedia)Coanda effect or wall-attachment effect, the tendency of a moving fluid, either liquid or gas, to attach itself to a surface and flow along it. As a fluid moves across a surface a certain amount of fr...

vortex

(Encyclopedia)vortex vôrˈtĕks [key], mass of fluid in whirling or rotary motion. To simplify the analysis, vortex motion usually describes motions in a frictionless fluid. In such cases the absence of friction w...

blister

(Encyclopedia)blister, puffy swelling of the outer skin (epidermis) caused by burn, friction, or irritants like poison ivy. A response of the body to protect deeper tissue, blisters generally contain serum, the liq...

work

(Encyclopedia)work, in physics and mechanics, transfer of energy by a force acting to displace a body. Work is equal to the product of the force and the distance through which it produces movement. Although both fo...

Reynolds number

(Encyclopedia)Reynolds number [for Osborne Reynolds], dimensionless quantity associated with the smoothness of flow of a fluid. It is an important quantity used in aerodynamics and hydraulics. At low velocities flu...

adhesion and cohesion

(Encyclopedia)adhesion and cohesion, attractive forces between material bodies. A distinction is usually made between an adhesive force, which acts to hold two separate bodies together (or to stick one body to anot...