A solid sphere and a hollow sphere of equal mass and radius roll down the same incline without slipping. Which reaches the bottom first?
JEE Main 2022 · Rotational Motion · medium
JEE 20224 options · 1 correct
A solid sphere and a hollow sphere of equal mass and radius roll down the same incline without slipping. Which reaches the bottom first?
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Answer: A
The solid sphere
Why
Acceleration while rolling is g sin(theta) / (1 + I/MR^2). The solid sphere has I = 2MR^2/5 and the hollow sphere has I = 2MR^2/3, so the solid sphere has the smaller rotational inertia factor, the larger acceleration, and arrives first.