Friction Force Formula

Friction Force Formula

Friction is a repelling force when one body is slipping through a surface. Friction is because of the contact between two surfaces. If frictional force is great, the movement of objects through the surface is not in a smooth manner. All through this movement, the kinetic energy is transformed to heat energy. Friction force is a derived force and not like gravitation i.e. a fundamental force. The formula for friction force is,

Where Ff is the friction, μ is the coefficient of friction force and  Fn is the normal force. It is a vector quantity.

Friction Force – Solved Examples

Let us answer some problems about friction force.

Problem 1: An object of mass 10kg is moving through a surface. Compute the friction force if the coefficient of friction is 0.2?

Answer:

Known variables are,
m = 10kg and μ = 0.2
Friction force formula is,
Ff = μFn
Fn can be computed as,
Fn = mg
= 10×9.81 = 98.1N
So, Ff = 0.2×98.1 = 19.62N

Problem  2: Calculate the friction force of a 5kg body which is moving through a surface with a friction coefficient 0.3?

Answer:

Known variables are,
m = 5kg and μ = 0.3
Friction force formula is,
Ff = μFn
Fn can be computed as,
Fn = mg
= 5×9.81 = 49.05N
So, Ff = 0.3×49.05 = 14.715N

 


Practise This Question

There were many gas molecules NH3,CO,CH4 and SO2 in a group once. They were discussing about who would be the better adsorbate on charcoal. So, they decided to have race among themselves to prove it as to who would be adsorbed more in the same time.
Who do you think won?