JEE Main 2012 — Rotational Motion Question with Solution
JEE Main 2012 (26 May Online)
Question
A thick-walled hollow sphere has outside radius . It rolls down an incline without slipping and its speed at the bottom is . Now the incline is waxed, so that it is practically frictionless and the sphere is observed to slide down (without any rolling). Its speed at the bottom is observed to be . The radius of gyration of the hollow sphere about an axis through its centre is
Choose an option
Show full solutionCorrect option: B
Correct answer
B
Step-by-step explanation
When body rolls dawn on inclined plane with velocity at bottom then body has both rotational and translational kinetic energy.
Therefore, by law of conservation of energy,
When body is sliding down then body has only translatory motion.
Dividing (i) by (ii) we get
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This is a previous-year question from JEE Main 2012, 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.