Question

Which one of the following statements is incorrect ?

(A) Coefficient of sliding friction has dimensions of length.

(B) Rolling friction is smaller than sliding friction.

(C) Frictional force oppose the relative motion.

(D) Limiting value of static friction is directly proportional to normal reactions.​

Answer 1

D) Rolling friction is smaller than sliding friction

Answer 2

The incorrect statement among the given statements is that coefficient of sliding friction has dimension of length.

• Option “A” is correct i.e. coefficient of sliding friction has dimension of length

• This statement is incorrect because coefficient of sliding friction has no dimension.

• The dimension of coefficient of sliding friction is as follows

$M^{0} L^{0}T^{0}$

so according to above equation, it is clear that sliding friction has no dimension.