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Friction 2.jpg


earlier, therapeutic rubbing of the limbs, from Middle French, from Latin friction-, frictio, from fricare to rub; akin to Latin friare to crumble, and perhaps to Sanskrit bhrīṇanti they injure


  • 1 a : the rubbing of one body against another
b : the force that resists relative motion between two bodies in contact
  • 2 : the clashing between two persons or parties of opposed views : disagreement
  • 3 : sound produced by the movement of air through a narrow constriction in the mouth or glottis


Several famous scientists and engineers contributed to our understanding of friction. They include Leonardo da Vinci, Guillaume Amontons, John Theophilus Desaguliers, Leonard Euler, and Charles-Augustin de Coulomb. Their findings are codified into these laws:

  • 1. The force of friction is directly proportional to the applied load. (Amontons' 1st Law)
  • 2. The force of friction is independent of the apparent area of contact. (Amontons' 2nd Law) (Amontons' 2nd Law does not work for elastic, deformable materials. For example, wider tires on cars provide more traction than narrow tires for a given vehicle mass because of surface deformation of the tire)
  • 3. Kinetic friction is independent of the sliding velocity. (Coulomb's Law of Friction)[1]