JEE Main 2024 · PhysicsNumerical answerNumerical valueEasyCalculation

JEE Main 30 January 2024, Shift 2, Physics Q52

Question 52 of 90 in this shift, Physics question 22 of 30, Section B.

Two discs of moment of inertia

I_1 = 4\ kg\,m^2

and

I_2 = 2\ kg\,m^2

, about their central axes & normal to their planes, rotating with angular speeds 10 rad/s & 4 rad/s respectively are brought into contact face to face with their axes of rotation coincident. The loss in kinetic energy of the system in the process is ________ J.

Official answer

NTA final key.

Chapter: System of Particles and Rotational Motion
Topic: Angular Momentum
Idea tested: Kinetic Energy Loss in Rotational Coupling

Same idea in other shifts

Asked 5× in all

30 Jan 2024, Shift 1 · Q52Consider a Disc of mass 5 kg, radius 2 m, rotating with angular velocity of 10 rad/s about an axis perpendicular to the plane of rotation.…EasyNumerical valueHas a figure
27 Aug 2021, Shift 2 · Q3Two discs have moments of intertia $I_1$ and $I_2$ about their respective axes perpendicular to the plane and passing through the centre.…EasySingle correct
2 Sep 2020, Shift 2 · Q4Two uniform circular discs are rotating independently in the same direction around their common axis passing through their centres. The…EasySingle correct
4 Sep 2020, Shift 1 · Q22A circular disc of mass M and radius R is rotating about its axis with angular speed $\omega_1$ . If another stationary disc having radius…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. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.