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Saturday, 31 October

JEE Main 2021 · PhysicsMultiple choiceDiagram basedHardMulti-step

JEE Main 18 March 2021, Shift 2, Physics Q4

Question 4 of 90 in this shift, Physics question 4 of 30, Section A.

A solid cylinder of mass m is wrapped with an inextensible light string and, is placed on a rough inclined plane as shown in the figure. The frictional force acting between the cylinder and the inclined plane is : [The coefficient of static friction, μs\mu_s, is 0.4]

The figure, in words

A right-triangle inclined plane (right angle at bottom right, angle 60° marked at bottom-left) with its vertical side on the right and its apex at top right attached to a hatched ceiling. A circle (cylinder, centre marked with a dot) sits against the inclined face; a string wrapped on the cylinder runs from the cylinder up, parallel to the incline, to the hatched ceiling at the top.
  1. (1)mg5\frac{mg}{5}Official answer
  2. (2)5 mg5\ mg
  3. (3)72 mg\frac{7}{2}\,mg
  4. (4)00

Official answer

Option 1

NTA final key.

Chapter
System of Particles and Rotational Motion
Topic
Friction
Idea tested
Direction of Static Friction

Same topic in other shifts

All Friction questions
  1. 2 Apr 2026, Shift 2 · Q27A 0.5 kg mass is in contact against the inner wall of a cylindrical drum of radius 4 m rotating about its vertical axis. The minimum…EasySingle correct
  2. 4 Apr 2026, Shift 1 · Q28The time taken by a block of mass mm to slide down from the highest point to the lowest point on a rough inclined plane is 50 %50\ \% more…MediumSingle correct
  3. 6 Apr 2026, Shift 2 · Q46A block takes tt time to slide down a plane inclined at 45∘45^\circ to the horizontal. If the surface is made smooth (frictionless), the…MediumNumerical value
  4. 4 Apr 2025, Shift 2 · Q44A block of mass 25 kg is pulled along a horizontal surface by a force at an angle 45∘45^\circ with the horizontal. The friction coefficient…MediumSingle correct
  5. 7 Apr 2025, Shift 1 · Q30A cubic block of mass m is sliding down on an inclined plane at 60∘60^\circ with an acceleration of g2\frac{g}{2}, the value of coefficient…EasySingle correct
  6. 4 Apr 2024, Shift 1 · Q33A wooden block, initially at rest on the ground, is pushed by a force which increases linearly with time t. Which of the following curve…MediumDiagram basedHas a figure

Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. This question needs a figure we do not reproduce; it is described in words above. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.