Question

A body of weight $w$ is lying at rest on a rough horizontal surface. If the angle of friction is $\theta$, then the minimum force required to move the body along the surface will be:

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

Answer 1

Answer: (B)

$w\tan \theta$

Here, the coefficient of friction is
$\mu =\tan \theta$
and $mg=w$
The minimum force, $F=f=\mu mg=w\tan \theta$