JEE Main 2021 · PhysicsNumerical answerNumerical valueEasyCalculation

JEE Main 25 July 2021, Shift 2, Physics Q22

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

A solid disc of radius 20 cm and mass 10 kg is rotating with an angular velocity of 600 rpm, about an axis normal to its circular plane and passing through its centre of mass. The retarding torque required to bring the disc at rest in 10 s is __________

\pi\times10^{-1}

Nm.

Official answer

NTA final key.

Chapter: System of Particles and Rotational Motion
Topic: Moment of Inertia
Idea tested: MOI of Standard Shapes

Same idea in other shifts

Asked 5× in all

6 Apr 2026, Shift 1 · Q31A solid sphere of radius 4 cm and mass 5 kg is rotating (rotation axis is passing through the centre of the sphere) with an angular…MediumSingle correct
12 Apr 2023, Shift 1 · Q53For a rolling spherical shell, the ratio of rotational kinetic energy and total kinetic energy is $\frac{x}{5}$ . The value of $x$ is ______MediumNumerical value
25 Jun 2022, Shift 2 · Q54Moment of Inertia (M.I.) of four bodies having same mass ‘ $M$ ’ and radius ‘ $2R$ ’ are as follows : $\mathrm{I}_1$ = M.I. of solid sphere…MediumNumerical value
9 Jan 2020, Shift 1 · Q22One end of a straight uniform 1 m long bar is pivoted on horizontal table. It is released from rest when it makes an angle $30^{\circ}$ …MediumNumerical valueHas a figure

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.