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Friday, 9 October

JEE Main 2020 · PhysicsNumerical answerNumerical valueMediumMulti-step

JEE Main 2 September 2020, Shift 1, Physics Q21

Question 21 of 75 in this shift, Physics question 21 of 25.

A small block starts slipping down from a point B on an inclined plane AB, which is making an angle θ\theta with the horizontal section BC is smooth and the remaining section CA is rough with a coefficient of friction μ\mu. It is found that the block comes to rest as it reaches the bottom (point A) of the inclined plane. If BC=2ACBC=2AC, the coefficient of friction is given by μ=ktan⁡θ\mu=k\tan\theta. The value of kk is ______.

The figure, in words

Inclined plane AB rising from A (angle theta with horizontal) up to B; point C lies between A and B on the incline; small block at B moving down.

Official answer

3.00

NTA final key (Sep 2020).

Chapter
Work, Energy and Power
Topic
Friction
Idea tested
Partially Rough Incline

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. 6 Apr 2024, Shift 2 · Q31A car of 800 kg is taking turn on a banked road of radius 300 m and angle of banking 30∘30^\circ. If coefficient of static friction is 0.2…MediumSingle correct

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 42 of the 174 JEE Main shifts held from 2017 to 2026.