A block kept on a rough inclined plane, as shown in the figure… | JEE Main 2019 (12 Jan, Shift 2)

Q21JEE Main 2019 · 12 JAN · SHIFT 2Medium

Friction on an Incline

A block kept on a rough inclined plane, as shown in the figure, remains at rest upto a maximum force 2 N down the inclined plane. The maximum external force up the inclined plane that does not move the block is 10 N. The coefficient of static friction between the block and the plane is: [Take g = 10 m/s2]

Show answer and solution

Answer: (c)

Max force down (friction up): $2 + mg\sin 30^\circ = \mu mg\cos 30^\circ$ .
Max force up (friction down): $10 = mg\sin 30^\circ + \mu mg\cos 30^\circ$ .
Subtracting: $8 = 2mg\sin 30^\circ \Rightarrow mg = 8\text{ N}$ ; then $\mu mg\cos 30^\circ = 6$ .
$\mu = \dfrac{6}{8 \times \sqrt{3}/2} = \dfrac{\sqrt{3}}{2}$
So the answer is (c) $\dfrac{\sqrt{3}}{2}$ .

Report a mistake

More questions on Friction on an Incline

A block of mass 10 kg is kept on a rough inclined plane as shown in the figure. A force…JEE Main 2019 (9 Jan, Shift 1)
A body of mass 2 kg slides down with an acceleration of 3 m/s2 on a rough inclined plane…JEE Main 2018 (15 Apr, Shift 2)
A given object takes n times more time to slide down a 45° rough inclined plane as it…JEE Main 2018 (15 Apr, Shift 1)
A rocket is fired vertically from the earth with an acceleration of 2g, where g is the…JEE Main 2016 (9 Apr, Shift 1)
A plank with a box on it at one end is gradually raised about the other end. As the angle…NEET 2015 (AIPMT)
A block of mass m is placed on a surface with a vertical cross section given by y = x³/6…JEE Main 2014
The upper half of an inclined plane of inclination θ is perfectly smooth while lower half…NEET 2013
A body starts from rest on a long inclined plane of slope 45°. The coefficient of…JEE Main 2013 (22 Apr, Shift 1)

Friction on an Incline question from JEE Main 2019 (12 Jan, Shift 2)

More questions on Friction on an Incline