Question

A block kept on a rough surface starts sliding when the inclination of the surface is $\theta$ with respect to the horizontal. The coefficient of static friction between the block and the surface is

• A. $\sin \theta$
• B. $\tan \theta$
• C. $\cos \theta$
• D. $\sec \theta$

Answer 1

Answer: (B)

As the block starts stipping for angle of inclination $\theta$, it must be equal to angle of repose given by
$\theta ={\tan }^{-1}{\mu }_s$
or ${\mu }_s=\tan \theta$