Moment of Inertia for Rotational Kinematics

AI Thread Summary
To find the moment of inertia for a bent thin uniform rod, the user initially considers the contribution from each segment of the rod, calculating it as I = (1/3)(m)(L^2/4) for each segment. They mistakenly conclude that the total moment of inertia is I = (m*L^2)/6, but this is incorrect. The correct approach involves integrating the mass distribution and considering the geometry of the bent rod. The user seeks clarification on the proper calculation method for this specific configuration. Accurate calculation of the moment of inertia is crucial for understanding rotational kinematics.
alco19357
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Homework Statement


A thin uniform rod of mass (M) and length (L) is bent at its center so that the two segments are now perpendicular to each other.

a. Find its moment of inertia about an axis perpendicular to its plane and passing through the point where the two segments meet.


Homework Equations


I = (integral) r^2 dm



I have a picture drawn (attached) but don't know how to proceed from here.

Thank you for any help
 

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Won't the inertia be twice that of a bar of length L/2 and mass M/2 about its end?
 
I would think that the moment of inertia would be:

I = (1/3)(m) [(L^2) / 4] for each rod...
= (m*L^2) / 12 for each rod

Therefore the total moment of inertia should be
I = (m*L^2) / 6 //sum of the two rodsBut it said that answer was wrong...

Thank you for the help
 
Thread 'Collision of a bullet on a rod-string system: query'
In this question, I have a question. I am NOT trying to solve it, but it is just a conceptual question. Consider the point on the rod, which connects the string and the rod. My question: just before and after the collision, is ANGULAR momentum CONSERVED about this point? Lets call the point which connects the string and rod as P. Why am I asking this? : it is clear from the scenario that the point of concern, which connects the string and the rod, moves in a circular path due to the string...
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