**Coefficient of Static Friction Formula**

Static Friction is a friction which is experienced when an object is placed on a surface. And, Kinetic friction is due to the movement of an object on a surface. Friction is well characterized by the coefficient of friction and is explained as the ratio between the frictional force and the normal force. This helps the object to lie on a surface. The coefficient of static friction is a scalar quantity and denoted as μs.

Formula for coefficient of static friction is,

Where, μsμs = coefficient of static friction

F = static frictional force

N = normal force

Solved Examples

Question 1: An object having a mass of 10kg is placed on a smooth surface. Static friction between these two surfaces is given as the 15N.Find the coefficient of static friction?

Solution:

Given ,

m = 10kg, F = 30N and μsμs = ?

We know that,

Normal force, N = mg

So, N = 10×× 9.81 = 98.1N

Formula for coefficient of static friction is,

μsμs = FNFN

μsμs = 3098.13098.1 = 0.305

Question 2: The normal force and the static frictional force of an object are 50N and 80N respectively. Find the coefficient of static friction?

Solution:

Given,

N = 50N, F = 80N and μsμs = ?

Formula for coefficient of static friction is,

μsμs = FNFN

μsμs = 80508050 = 1.6