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Moment Of Inertia Of A Rod - Practice Questions & MCQ

Edited By admin | Updated on Sep 18, 2023 18:34 AM | #JEE Main

Quick Facts

  • Moment of inertia of a Rod is considered one of the most asked concept.

  • 8 Questions around this concept.

Solve by difficulty

The moment of inertia of a uniform cylinder of length land radius R about its perpendicular bisector is I.  What is the ratio \frac{l}{R} such that the moment of inertia is minimum?

Concepts Covered - 1

Moment of inertia of a Rod

Let I=Moment of inertia of a ROD about an axis through its centre and perpendicular to it

To calculate I (Moment of inertia of rod)

Consider a uniform straight rod   of length L, mass M and having centre C

 mass per unit length of the rod = \lambda = \frac{M}{L}

Take a small element of mass dm with length dx at a distance x from the point C.

dm = \lambda.dx = \frac{M}{L}.dx

       \Rightarrow dI= x^2dm

Now integrate this dI  between the limits  x = -\frac{L}{2}\ to \ \frac{L}{2}

I=\int dI=\int x^2dm=\int_{\frac{-L}{2}}^{\frac{L}{2}} \frac{M}{L}x^2*dx= \frac{M}{L}\int_{\frac{-L}{2}}^{\frac{L}{2}}x^2dx=\frac{ML^2}{12}

 

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Moment of inertia of a Rod

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