Question

An object of mass m rests on a plane inclined at an angle of $\theta$. What is the maximum value for the coefficient of static friction at which the object will slide down the incline?

• A. $sin\theta -cos\theta$
• B. $cos\theta -sin\theta$
• C. $mgsin\theta$
• D. $sin\theta /cos\theta$
• E. $sin\theta +cos\theta$

Answer 1

Answer: (D)

$sin\theta /cos\theta$

The block would continue to slide down unless the force of sliding friction is less than the downward force.

$⟹mgsin\theta >{\mu }_{s}N$

$⟹mgsin\theta >{\mu }_{s}mgcos\theta$

$⟹{\mu }_s<\frac{sin\theta }{cos\theta }$