JEE Main 2020 — Rotational Motion Question with Solution
From: JEE Main 2020 (Online) 6th September Evening Slot
Question
The linear mass density of a thin rod AB of length L varies from A to B as
, where x is the distance from A. If M is the mass of the rod then its moment of inertia about an axis passing through A and perpendicular to the rod is :
, where x is the distance from A. If M is the mass of the rod then its moment of inertia about an axis passing through A and perpendicular to the rod is :
Choose an option
Show full solutionCorrect option: C
Correct answer
C
Step-by-step explanation
dm = dx
= dx
Integrating both side, we get
M = =
.....(1)
Moment of inertia of small part dx is
dI = dmx2
Integrating both side, we get
I =
=
=
=
Here by putting the value of 0 form (1)
I = =
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This is a previous-year question from JEE Main 2020, covering the Rotational Motion chapter of Physics. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.