# 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.

The Retarding force observed as kinetic friction in the two moving aircraft as they touch with each other. The kinetic friction is expressed as

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

Where,

Fk is Force of kinetic friction
the coefficient of kinetic friction is μk
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 of frictional force is newton (N) and coefficient of kinetic friction will be a unit-less quantity.

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

Kinetic Friction Solved Example

Problem 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:

μk = 0.8

Fn = 200 N

The formula of kinetic friction is

Fk = μk Fn

Fk = 0.8 × 200

Fk = 160 N