Editing Friction (section)

===Devices===
Devices such as wheels, [[ball bearing]]s, [[roller bearing]]s, and air cushion or other types of [[fluid bearing]]s can change sliding friction into a much smaller type of rolling friction.

Many [[thermoplastic]] materials such as [[nylon]], [[HDPE]] and PTFE are commonly used in low friction [[Bearing (mechanical)|bearings]]. They are especially useful because the coefficient of friction falls with increasing imposed load.<ref>{{Cite journal |author=Valentin L. Popov |author2=Lars Voll |author3=Stephan Kusche |author4=Qiang Li |author5=Svetlana V. Rozhkova |date=2018|title=Generalized master curve procedure for elastomer friction taking into account dependencies on velocity, temperature and normal force|journal=Tribology International|volume=120|pages=376–380|doi=10.1016/j.triboint.2017.12.047|arxiv=1604.03407|s2cid=119288819}}</ref> For improved wear resistance, very high [[molecular weight]] grades are usually specified for heavy duty or critical bearings.