Moment of inertia for a cylinder at a distance from rotation axis

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SUMMARY

The discussion focuses on calculating the inertia tensor for a cylinder when the rotational axis is either the x-axis or y-axis. The inertia tensor for a cylinder is established, with the bottom right element remaining constant as it pertains to rotation around the z-axis. The participant expresses uncertainty regarding the diagonal form of the matrix and the calculation of moments of inertia when the axis of rotation changes. The key insight is the potential simplification of using the height (h) of the cylinder in the inertia tensor matrix.

PREREQUISITES
  • Understanding of inertia tensors and their properties
  • Familiarity with rotational dynamics and moments of inertia
  • Basic knowledge of matrix representation in physics
  • Concept of parallel axis theorem for calculating moments of inertia
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  • Study the derivation of the inertia tensor for a solid cylinder
  • Learn about the parallel axis theorem and its application
  • Explore the calculation of moments of inertia for different shapes
  • Investigate the implications of changing the axis of rotation on inertia tensors
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Homework Statement


I have a cylinder, for which i want to find the inertia tensor.
http://www.mip.sdu.dk/~pino/inertiacyl.JPG
Where the rotational axis are either the x (red) or y (green).


Homework Equations


I know that the inertia tensor for a cylinder is of the form
http://www.mip.sdu.dk/~pino/inertiamoment-cylinder.jpg
Then I believe that the bottom right element stays the same, since this describes the rotation around the z-axis.
The tricky part for me is the rest of the matrix. I am no expert, and do not understand inertia tensors fully, so I would like some pointers.


The Attempt at a Solution


My immediate idea is that the matrix should remain in its diagonal form, the zeros will remain zeros, is this correct?

I know that for complex forms i can split up the moments of inertia, so i have the moment of inertia for the blank space d, which is 0. and then i can add the moment of inertia of the cylinder, but how do i calculate this, when the rotational axis is x-axis for example?
 
Physics news on Phys.org
I had a sudden struck of enlightment...
Is it really as simple as just taking d+h and and using as h in the matrix?
 

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