# Kinetic Friction Formula

We witness in our day-to-day life the frictional force taking place in moving bodies which are in interaction. This is called kinetic friction. Rolling friction and sliding friction falls under this topic.

TheÂ RetardingÂ forceÂ observedÂ as kinetic frictionÂ inÂ theÂ twoÂ movingÂ aircraftÂ asÂ theyÂ touchÂ withÂ eachÂ other. The kinetic friction is expressed as

$F_{k}=\mu_{k}F_{n}$

Where,

Fk isÂ Force of kinetic friction
the coefficient of kinetic friction is Î¼k
the normal force is Fn

Kinetic friction formula is handy for questions to compute the friction amid the bodies which are in motion. The unit ofÂ frictional force isÂ newton (N) andÂ coefficient of kinetic friction will be a unit-less quantity.

TheÂ related concepts of friction are listed below in the table:

Kinetic Friction Solved Example

ProblemÂ 1:A boy is playing volleyball then calculate the kinetic friction if the friction coefficient is 0.8 and thrown with the force of 200N?

Given:

Î¼kÂ = 0.8

FnÂ = 200 N

The formula of kinetic friction is

FkÂ =Â Î¼kÂ Fn

FkÂ = 0.8 Ã— 200

FkÂ = 160 N