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Saturday, 31 October

JEE Main 2025 · PhysicsMultiple choiceSingle correctMediumMulti-step

JEE Main 2 April 2025, Shift 1, Physics Q28

Question 28 of 75 in this shift, Physics question 3 of 25, Section A.

A cord of negligible mass is wound around the rim of a wheel supported by spokes with negligible mass. The mass of wheel is 10 kg and radius is 10 cm and it can freely rotate without any friction. Initially the wheel is at rest. If a steady pull of 20 N is applied on the cord, the angular velocity of the wheel, after the cord is unwound by 1 m, would be :

The figure, in words

Wheel (circle) with radius R marked from centre to rim; a cord wound on the rim hangs vertically down from the right side of the rim with a downward force F = 20 N applied at its end.
  1. (1)10 rad/s
  2. (2)20 rad/sOfficial answer
  3. (3)30 rad/s
  4. (4)0 rad/s

Official answer

Option 2

NTA final key.

Chapter
System of Particles and Rotational Motion
Topic
Torque and Equilibrium
Idea tested
Work Done by Constant Torque

Same idea in other shifts

Asked 2× in all
  1. 30 Jul 2022, Shift 2 · Q28A fly wheel of mass 10 kg and radius 50 cm is rotating at a rate of 360 rpm. Assuming mass to be concentrated at the rim, the constant…MediumNumerical 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. 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.