JEE Mains · Physics · STD 11 - System of particles and rotational motion
- JEE Mains 2021
- Hard
- Numerical
The following bodies, \((1)\) a ring \((2)\) a disc \((3)\) a solid cylinder \((4)\) a solid sphere, of same mass \(m\) and radius \(R\) are allowed to roll down without slipping simultaneously from the top of the inclined plane. The body which will reach first at the bottom of the inclined plane is ........... [Mark the body as per their respective numbering given in the question]

Pick an option to check your answer.
Answer & Solution
Correct Answer
(C) \(4\)
Step-by-step Solution
Detailed explanation
\(Mg \sin \theta R =\left( mk ^{2}+ mR ^{2}\right) \alpha\)
\(\alpha=\frac{ Rg \sin \theta}{ k ^{2}+ R ^{2}} \Rightarrow a =\frac{ g \sin \theta}{1+\frac{ k ^{2}}{ R ^{2}}}\)
\(t =\sqrt{\frac{2 s }{ a }}=\sqrt{\frac{2 s }{ g \sin \theta}\left(1+\frac{ k ^{2}}{ R ^{2}}\right)}\)
for least time, \(k\) should be least \(\&\) we know \(k\) is least for solid sphere.
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