Notes

Angle of Friction…

Angle of Friction – It is defined as the angle between the normal reaction ® and the resultant of the frictional force (fs) and reaction R, as shown in figure.

In △AOB, tanθ = AB/OB = fs/R = µsR/R or tanθ = µs ⇒ θ = tan-1s) i.e. Coefficient of limiting friction between any two surfaces in contact is equal to tangent of the angle of friction between them.