JEE Main 2020 — Rotational Motion Question with Solution
From: JEE Main 2020 (Online) 4th September Morning Slot
Question
A circular disc of mass M and radius R is rotating about its axis with angular speed
. If another
stationary disc having radius and same mass M is droped co-axially on to the rotating disc.
Gradually both discs attain constant angular speed
the energy lost in the process is p% of the
initial energy. Value of p is __________.
Enter your answer
Show full solutionCorrect answer: 20
Correct answer
20
Step-by-step explanation
loss of K.E. =
= 100
= 100 =
= 20%
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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.