JEE Main 2019PhysicsRotational MotionMediumMCQ

JEE Main 2019 — Rotational Motion Question with Solution

JEE Main 2019 (09 Jan Shift 2)

Question

A rod of length 50 cm is pivoted at one end. It is raised such that it makes an angle of 30o from the horizontal as shown and released from rest. Its angular speed when it passes through the horizontal (in rad s-1 ) will be g=10 ms-2

Choose an option

Show full solutionCorrect option: B
Correct answer
B30

Step-by-step explanation

From conservation of mechanical energy


Loss in gravitational PE= gain in KE

mgl2sin⁡30o=12Iω2

mgl2sin⁡30o=12ml23ω2

ω=3g2l=3×102×50×10-2=30 rad/s

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About this question

This is a previous-year question from JEE Main 2019, 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.