JEE Mains · Physics · STD 11 - 6. system of particles and rotational motion
If a solid sphere of mass \(5\,kg\) and a disc of mass \(4\,kg\) have the same radius. Then the ratio of moment of inertia of the disc about a tangent in its plane to the moment of inertia of the sphere about its tangent will be \(\frac{x}{7}\). The value of \(x\) is \(.........\)
- A \(4\)
- B \(5\)
- C \(3\)
- D \(2\)
Answer & Solution
Correct Answer
(B) \(5\)
Step-by-step Solution
Detailed explanation
\(I _1=\frac{2}{5} m _1 R ^2+ m _1 R ^2\) \(I _1= m _1 R ^2\left(\frac{7}{5}\right)\) \(I _1=7 R ^2\) \(I _2=\frac{ m _2 R ^2}{4}+ m _2 R ^2\) \(I _2=\frac{5}{4} m _2 R ^2\) \(I _2=5 R ^2\) \(\frac{ I _2}{ I _1}=\frac{5}{7}\) \(x =5\)
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