Q. A block of mass $\sqrt{3}$ kg resting on a horizontal surface. A force $F$ is applied on the block as shown in figure. If coefficient of friction between the block be $\ \frac{1}{2\sqrt{3}}$, what can be the maximum value of force $F$ so that block does not start moving? (Take $g = 10\ ms^{- 2}$)

A) 20 N
B) 10 N
C) 12N
D) 15 N
Explanation

(a) From acting on block are shown in adjoining figure
As the block does not move, hence
$F\cos{60{^\circ} = f = \mu N = \mu\left( Mg + F\sin 60{^\circ} \right)}$
[image:5_image197.emf]
$\therefore F\frac{1}{2} = \frac{1}{2\sqrt{3}}\left( \sqrt{3} \times 10 + F \bullet \frac{\sqrt{3}}{2} \right)$
On simplification, we get $F = 20$ N

Dr. Abubacker
Reviewed by Dr. Abubacker

Physics Educator & NEET/JEE Specialist

Ph.D. in Physics with 19+ years of teaching experience.

Want more practice?
Practice Laws Of Motion MCQs