Question

When the body which is applied forces come in the stage of the limiting friction then the body is termed as to come in ___________ equilibrium.

(a) Unstable

(b) Stable

(c) Non-stable

(d) Improper Stable

This question was addressed to me during an interview.

My enquiry is from Characteristics of Dry Friction topic in portion Friction of Engineering Mechanics

Answer 1

Correct answer is (a) Unstable

To explain: As the limiting friction is the maximum value of the frictional forces. Thus if more force is applied to the body then the body is going to move forward. Because the two surfaces are in contact and the friction applies at that surface only, resisting the motion of the surface. Thus the name unstable equilibrium.