A body of mass m rests on horizontal surface. coefficient of friction between body and surface is μ

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4-2.Friction

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A body of mass m rests on 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 body and surface will be

A

$\mu mg$

B

$\mu \,\left[ {mg + \left( {\frac{P}{2}} \right)} \right]$

C

$\mu \,\left[ {mg - \left( {\frac{P}{2}} \right)} \right]$

D

$\mu \,\left[ {mg - \left( {\frac{{\sqrt 3 \,P}}{2}} \right)} \right]$

Solution

(c) Normal reaction $R = mg – P\sin {30^o}$ $ = mg – \frac{P}{2}$

Limiting friction between body and surface is given by,

$F = \mu R = \mu \left( {mg – \frac{P}{2}} \right)$.

Standard 11

Physics

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