The frictions are interaction S which are opposed to the persistence of a relative movement between two systems in contact.

The Science of frictions is tribology.

See also: Tribology

Tribology is complicated by the fact that frictions are not due to a elementary Interaction but result from various causes, mainly of the electromagnetic forces and of the Interaction of exchange between the atoms of surfaces in contact. These same forces are also concerned in the Adhérence (being opposed to the creation of a movement), which for this reason can be studied jointly.

In the objective to simplify, it is sometimes refers to the " friction solide" and with the " friction fluide" , but this classification is nonrelevant and inoperative, simplification concerned is thus not reached.

Frictions intervene in the large majority of the physical phenomena of the everyday life. They are sometimes exploited (for example for the Freinage, the Sciage, the Polissage, the Lavage, etc), but they also have annoying consequences (Usure, loss of energy and Rendement, heating, etc) for the living beings and of many technological and economic applications.

History

The omnipresence of frictions led a long time so that they are not regarded interactions but as fundamental characteristics of nature. Thus, in physics aristotelician, one considered that the objects could maintain their movement only if one force continued to be exerted on them. It was mainly the observation of the astronomical movements, for which the influence of frictions is negligible, which brought to the questioning of this physics and to the establishment of the Newtonian Mécanique.

See too

• Tribology
• Mechanical Curve of Stribeck
• of the Mechanical solid
• of the fluids

Simple: Friction

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