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Saturday, 31 October

JEE Main 2021 · PhysicsNumerical answerNumerical valueMediumCalculation

JEE Main 26 February 2021, Shift 1, Physics Q21

Question 21 of 90 in this shift, Physics question 21 of 30, Section B.

As shown in the figure, a block of mass 3\sqrt{3} kg is kept on a horizontal rough surface of coefficient of friction 133\frac{1}{3\sqrt{3}}. The critical force to be applied on the vertical surface as shown at an angle 60∘60^{\circ} with horizontal such that it does not move, will be 3x3x. The value of xx will be __________. [g=10 m/s2[\mathrm{g}=10\ \mathrm{m/s^2} ; sin⁡60∘=32\sin 60^{\circ}=\frac{\sqrt{3}}{2} ; cos⁡60∘=12]\cos 60^{\circ}=\frac{1}{2}]

The figure, in words

Drawn: a square block labelled m = 3\sqrt{3} kg resting on a horizontal ground line; on its left an arrow points to the ground contact with the label μ=133\mu=\frac{1}{3\sqrt{3}}. On the right, four parallel slanting arrows point down-left onto the block's right vertical face, and the angle 60° is marked between the slanting direction and the horizontal ground line at the bottom right.

Official answer

3

NTA final key.

Chapter
Laws of Motion
Topic
Friction
Idea tested
Impending Motion Analysis

Same idea in other shifts

Asked 2× in all
  1. 17 Mar 2021, Shift 2 · Q22A boy of mass 4 kg is standing on a piece of wood having mass 5 kg. If the coefficient of friction between the wood and the floor is 0.5,…HardNumerical valueHas 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.