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4-2.Friction
medium
A block of mass $10 \,kg$ is held at rest against a rough vertical wall $[\mu=0.5]$ under the action a force $F$ as shown in figure. The minimum value of $F$ required for it is ............ $N$ $\left(g=10 \,m / s ^2\right)$
A$162.6$
B$89.7$
C$42.7$
D$95.2$
Solution
(b)
$N=F \sin 30^{\circ}=F / 2$
$F \cos 30^{\circ}+\mu N=(10) g$
$\frac{F \sqrt{3}}{2}+0.5\left(\frac{F}{2}\right)=100$
$F\left(\frac{2 \sqrt{3}+1}{4}\right)=100$
$F \simeq 89.7 \,N$
$N=F \sin 30^{\circ}=F / 2$
$F \cos 30^{\circ}+\mu N=(10) g$
$\frac{F \sqrt{3}}{2}+0.5\left(\frac{F}{2}\right)=100$
$F\left(\frac{2 \sqrt{3}+1}{4}\right)=100$
$F \simeq 89.7 \,N$
Standard 11
Physics
