The coefficient of friction between any two surfaces in contact is defined as the ratio of the force of limiting friction and normal reaction between them.
μ = \(\frac{F}{R}\)
Angle with the resultant of force of limiting friction F and normal reaction R makes with the direction of normal reaction R is angle of reaction.
Relation :
In ∆ AOC tan θ = \(\frac{AC}{OA}=\frac{OB}{OA}=\frac{F}{R}\) = μ
Hence, μ = tan θ
