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 topic in other shifts

All Angular Momentum questions

2 Apr 2026, Shift 1 · Q29The position of an object having mass $0.1$ kg as a function of time $t$ is given as $\vec r=\left(10t^2\hat i+5t^3\hat j\right)$ m. At…MediumOther
4 Apr 2025, Shift 2 · Q50A solid sphere with uniform density and radius R is rotating initially with constant angular velocity $(\omega_1)$ about its diameter.…MediumNumerical value
8 Apr 2025, Shift 2 · Q47A thin solid disk of 1 kg is rotating along its diameter axis at the speed of 1800 rpm. By applying an external torque of $25\pi$ Nm for…MediumNumerical value
31 Jan 2024, Shift 2 · Q51A body of mass ' $m$ ' is projected with a speed ' $u$ ' making an angle of $45^\circ$ with the ground. The angular momentum of the body about…MediumNumerical value
29 Jun 2022, Shift 1 · Q34A spherical shell of 1 kg mass and radius R is rolling with angular speed $\omega$ on horizontal plane (as shown in figure). The magnitude…MediumSingle correctHas a figure
25 Jul 2021, Shift 1 · Q25A particle of mass ' $m$ ' is moving in time ' $t$ ' on a trajectory given by $\vec{r}=10\alpha t^2\hat{i}+5\beta(t-5)\hat{j}$ Where $\alpha$ …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 42 of the 174 JEE Main shifts held from 2017 to 2026.