Calculating Moment of Inertia help

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Homework Help Overview

The discussion revolves around calculating the moment of inertia for a flat rectangular plate with a specified axis of rotation. Participants are exploring the appropriate formulas and concepts related to this topic.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants are attempting to understand the moment of inertia for a rectangular plate and are referencing various sources for equations. There are questions about the derivation of specific formulas and the relevance of the parallel axis theorem.

Discussion Status

The discussion includes attempts to clarify the correct formula for the moment of inertia and its derivation. Some participants are providing links to resources, while others are questioning the applicability of certain equations and seeking further clarification.

Contextual Notes

There is mention of confusion regarding the distinction between area moment of inertia and mass moment of inertia, as well as the need for a complete derivation involving calculus and integration.

paddlewheel99
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How to Calculate Moment of Inertia for a flat rectangular plate of length 'l' & width 'w' with axis of rotation along the width 'w' (the axis of rotation is parrallel to edge of width)
 
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paddlewheel99 said:
How to Calculate Moment of Inertia for a flat rectangular plate of length 'l' & width 'w' with axis of rotation along the width 'w' (the axis of rotation is parrallel to edge of width)

This should help you out:

http://en.wikipedia.org/wiki/Moment_of_inertia

.
 
No actually it is not easy as it looks. After doing a lot of googling, i got the required equation on http://en.wikipedia.org/wiki/List_of_area_moments_of_inertia
the equation is: I = bh^3/3
Can anyone give a link to the complete derivation of this formula or provide it themselve.
With the complete calculus and intergration involved in it.
Also will the parrallel axis theorem have any role in the derivation.
Thank You
 
paddlewheel99 said:
the equation is: I = bh^3/3
Careful... that's the area moment of inertia. (You'd need to multiply by the density.)

What you want is simpler (but equivalent, of course). Hint: Can you find the moment of inertia of a stick (thin rod) about one end? That's the same problem, believe it or not.
 

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