The maximum value of static friction upto which body does not move is called limiting friction.
(i) The magnitude of limiting friction between any two bodies in contact is directly proportional to the normal reaction between them.
F1 ∝ R or F1 = µs R
(ii) Direction of the force of limiting friction is always opposite to the direction in which one body is at the verge of moving.
(iii) Coefficient of static friction :
(a) µs is called coefficient of static friction.
(b) Dimension : [M0L0T0]
(c) Unit : It has no unit.
(d) Value of µs lies in between 0 and 1
(e) Value of µ depends on material and nature of surfaces in contact.
(f) Value of µ does not depend upon apparent area of contact.
