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Saturday, 31 October

JEE Main 2022 · PhysicsMultiple choiceSingle correctEasyCalculation

JEE Main 29 July 2022, Shift 2, Physics Q46

Question 46 of 90 in this shift, Physics question 16 of 30, Section A.

The torque of a force 5i^+3j^−7k^5\hat{i}+3\hat{j}-7\hat{k} about the origin is τ\tau. If the force acts on a particle whose position vector is 2i^+2j^+k^2\hat{i}+2\hat{j}+\hat{k}, then the value of τ\tau will be
  1. (1)11i^+19j^−4k^11\hat{i}+19\hat{j}-4\hat{k}
  2. (2)−11i^+9j^−16k^-11\hat{i}+9\hat{j}-16\hat{k}
  3. (3)−17i^+19j^−4k^-17\hat{i}+19\hat{j}-4\hat{k}Official answer
  4. (4)17i^+9j^+16k^17\hat{i}+9\hat{j}+16\hat{k}

Official answer

Option 3

NTA final key.

Chapter
System of Particles and Rotational Motion
Topic
Torque and Equilibrium
Idea tested
Torque Calculation

Same idea in other shifts

Asked 7× in all
  1. 9 Apr 2024, Shift 1 · Q52A string is wrapped around the rim of a wheel of moment of inertia 0.40 kgm20.40\ \mathrm{kgm^2} and radius 1010 cm. The wheel is free to rotate…EasyNumerical value
  2. 10 Apr 2023, Shift 2 · Q53A force of −Pk^-P\hat{k} acts on the origin of the coordinate system. The torque about the point (2, -3) is P(ai^+bj^)P(a\hat{i} + b\hat{j}). The…MediumNumerical value
  3. 13 Apr 2023, Shift 2 · Q52A light rope is wound around a hollow cylinder of mass 5 kg and radius 70 cm. The rope is pulled with a force of 52.5 N. The angular…MediumNumerical value
  4. 4 Aug 2021, Shift 1 · Q19The moment of force F‾=2i^+j^+2k^\overline{F}=2\hat{i}+\hat{j}+2\hat{k} acting at a point −i^+2j^+k^-\hat{i}+2\hat{j}+\hat{k} about the point…EasySingle correct
  5. 16 Mar 2021, Shift 2 · Q24A force F⃗=4i^+3j^+4k^\vec{F}=4\hat{i}+3\hat{j}+4\hat{k} is applied on an intersection point of x=2x=2 plane and xx-axis. The magnitude of torque of…EasyNumerical value
  6. 5 Sep 2020, Shift 1 · Q22A force F⃗=(i^+2j^+3k^)\vec{F} = (\hat{i} + 2\hat{j} + 3\hat{k})N acts at a point (4i^+3j^−k^)(4\hat{i} + 3\hat{j} - \hat{k})m. Then the magnitude of torque…EasyNumerical value

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. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.