Answer:
Step-by-step explanation:
Coefficient of friction is a constant ratio of two forces acting on a body at same time.
This ratio is represented by a letter μ. Suppose forces acting on a body due to its surface and due to pressure applied on it be F and L respectively.
Now as μ = F/L and both F and L are measured in term of force, then μ is a dimensionless quantity and do not have any unit.