Q 11-04-038NEETJEE MainEasy
A block placed on a plank just begins to slide when the plank is tilted to $30°$ with the horizontal. The coefficient of static friction between the block and the plank is
Answer: (C) $\dfrac{1}{\sqrt{3}}$
Concept. At the angle of repose $\mu_s = \tan\theta$.
Step 1. Substitute. $\tan30° = \dfrac{1}{\sqrt3}$.
Answer. $\dfrac{1}{\sqrt3}$ (Option C).
Solution by Sreeraj P, M.Sc Physics