# Kinetic Friction Formula

## 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 witnessed in the two moving planes when they are in interaction with each other is termed as Kinetic Friction. Kinetic Friction Formula is articulated as:

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

Where,
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.

Kinetic Friction Solved Examples

Underneath are problems on kinetic friction which may be useful to you.

Problem 1: A boy is playing with football. Compute the kinetic friction if the friction coefficient is 0.5 and is kicked with the force of 150 N?

Given:

Coefficient of friction μk = 0.5,
Normal force Fn = 150 N,
The Kinetic friction is articulated by Fk = μk Fn
= 0.5 × 150
= 75 N.
Problem 2: A car is traveling at a uniform speed with normal force of 1000 N. If the kinetic friction applied on the car is 500 N. Compute the coefficient of kinetic friction?

Known:

Normal force Fn = 1000 N,
Kinetic friction Fk = 500 N,

The coefficient of kinetic energy is given by

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

$\frac{500}{1000}$

=0.5

#### Practise This Question

Siblings share ____% of their genes while fraternal twins share ____% and identical twins share ____% of their genes (on average).