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Saturday, 31 October

JEE Main 2023 · PhysicsNumerical answerNumerical valueMediumCalculation

JEE Main 11 April 2023, Shift 2, Physics Q53

Question 53 of 90 in this shift, Physics question 23 of 30, Section B.

A circular plate is rotating in horizontal plane, about an axis passing through its center and perpendicular to the plate, with an angular velocity ω\omega. A person sits at the center having two dumbbells in his hands. When he stretches out his hands, the moment of inertia of the system becomes triple. If E be the initial Kinetic energy of the system, then final Kinetic energy will be Ex\frac{E}{x}. The value of xx is

Official answer

3

NTA final key.

Chapter
System of Particles and Rotational Motion
Topic
Angular Momentum
Idea tested
Conservation of Angular Momentum

Same idea in other shifts

Asked 7× in all
  1. 6 Apr 2024, Shift 1 · Q56If the radius of earth is reduced to three-fourth of its present value without change in its mass then value of duration of the day of…MediumNumerical value
  2. 8 Apr 2024, Shift 2 · Q35A thin circular disc of mass M and radius R is rotating in a horizontal plane about an axis passing through its centre and perpendicular…EasySingle correct
  3. 10 Apr 2023, Shift 1 · Q53If the earth suddenly shrinks to 164\frac{1}{64}th of its original volume with its mass remaining the same, the period of rotation of earth…MediumNumerical value
  4. 26 Jun 2022, Shift 1 · Q35A thin circular ring of mass M and radius R is rotating with a constant angular velocity 2 rads−1\mathrm{rads^{-1}} in a horizontal plane…EasySingle correct
  5. 18 Mar 2021, Shift 1 · Q20A thin circular ring of mass M and radius r is rotating about its axis with an angular speed ω\omega. Two particles having mass m each…EasySingle correct
  6. 5 Sep 2020, Shift 1 · Q4A wheel is rotating freely with an angular speed ω\omega on a shaft. The moment of inertia of the wheel is I and the moment of inertia of…EasySingle 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. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.