Coefficient of restitution

From Simple English Wikipedia, the free encyclopedia

The coefficient of restitution (COR, also denoted by e), is the ratio of the final to initial relative speed between two objects after they collide. It is also defined as the ratio velocity of separation to velocity of approach.[1]

The value is almost always equal to 1or less than 1 due to initial translational kinetic energy being lost to rotational kinetic energy, plastic deformation, and heat. Mathematically

Coefficient of restitution (e)= Velocity of separation/Velocity of approach. Coefficient of restitution is always =1<1. Coefficient of restitution was postulated and developed by Sir Isaac Newton.[2]

Range of values for e – treated as a constant[change | change source]

e is mostly a positive, real number between 0 and 1:

e = 0: This is known as perfectly inelastic collision. It implies that kinetic energy along the common normal is 0. Kinetic energy is converted to heat or work done in deforming the objects.

0 < e < 1: This is a inelastic collision, in which some kinetic energy is dissipated. It can also achieve both in practical and in mathematical calculation.[3]

References[change | change source]

  1. "What is coefficient of restitution?". Archived from the original on 2021-11-20. Retrieved 2021-11-20.
  2. Weir, Graham; McGavin, Peter (2008-05-01). "The coefficient of restitution for the idealized impact of a spherical, nano-scale particle on a rigid plane". Proceedings of the Royal Society of London Series A. 464 (2093): 1295–1307. Bibcode:2008RSPSA.464.1295W. doi:10.1098/rspa.2007.0289. ISSN 0080-4630. S2CID 122562612.
  3. Kuninaka, Hiroto; Hayakawa, Hisao (2004-10-05). "Anomalous Behavior of the Coefficient of Normal Restitution in Oblique Impact". Physical Review Letters. 93 (15): 154301. arXiv:cond-mat/0310058. Bibcode:2004PhRvL..93o4301K. doi:10.1103/PhysRevLett.93.154301. hdl:2433/50060. PMID 15524884. S2CID 23557976.