Question

A body of mass $m$ rests on a horizontal surface. The coefficient of friction between the body and the surface is $\mu$. If the mass is pulled by a force $P$ as shown in the figure, the limiting friction between the body and surface will be

• A. $\mu mg$
• B. $\mu [mg+\left(\frac{P}{2}\right)]$
• C. $\mu [mg-\left(\frac{P}{2}\right)]$
• D. $\mu [mg-\left(\frac{\sqrt{3}P}{2}\right)]$

Answer 1

The correct option is C $\mu [mg-\left(\frac{P}{2}\right)]$

Normal reaction
$N=mg-P\sin {30}^{\circ }$
$=mg-\frac{P}{2}$
$\therefore$ Limiting friction between the body and the surface
$=\mu N=\mu [mg-\frac{P}{2}]$
Hence, the correct answer is option (c).