Which one of the following statements is incorrect ?

Options

A. Frictional force opposes the relative motion.
B. Limiting value of static friction is directly proportional to normal reaction.
C. Rolling friction is smaller than sliding friction
D. Coefficient of sliding friction has dimensions of length.

Answer

D

Explanation

Coefficient of sliding friction has no dimension
`f=mu_(s)N`
`implies mu_(s)=(f)/(N)`