Question

What is the dimension for coefficient of friction?

(a) [M][L][T]

(b) [M][L][T]^2

(c) It has no dimensions

(d) [M][L]^-1[T]^-1

I got this question by my school teacher while I was bunking the class.

This key question is from Methods of Determination of Coefficient of Viscosity topic in chapter Viscous Flow & Turbulent Flow of Fluid Mechanics

Answer 1

Right choice is (c) It has no dimensions

The best explanation: Coefficient of static friction is defined as the ratio of limiting frictional force to the normal reaction force. Dividing the dimensions of the limiting frictional force and normal frictional force, the units cancel out each other due to which it has no dimensions.