If an object just begins to slide on a surface inclined at 30° to the horizontal, the coefficient of friction is?

A. √3
B. √3/2
C. 1/√2
D. 1/√3

Correct Answer:

Option D – 1/√3

Explanation

A body sliding down a plane inclined at 30° to the horizontal, has coefficient of friction
= tan 30° = 1/√3