Moment of Inertia: Mass, Radius, Formula

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Homework Help Overview

The discussion revolves around calculating the moment of inertia for a solid disk with a specified diameter and mass. Participants are exploring the appropriate formula to use in this context.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • The original poster attempts to apply the formula I = mr^2, but questions its validity for a solid disk. Other participants suggest looking up the correct formula for the moment of inertia of a disk.

Discussion Status

The discussion includes some tension regarding the interpretation of the formula and the nature of the problem. While some participants express frustration, there is an acknowledgment of the challenges faced by those new to the subject. Guidance has been offered to seek the correct formula, indicating a potential direction for resolution.

Contextual Notes

Participants are navigating the complexities of physics concepts, with some expressing stress related to learning new material. There is a recognition of the need for courtesy in communication during the learning process.

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1. Determine the moment-of-inertia in kg/m^2 of a solid disk 0.51 m in diameter, having a mass of 5.0 kg.



2. I=mr^2



3. I thought the formula was I = mr^2. Mass = 5kg and the radius = .255m, but when I enter the answer of .325 it is incorrect. Am I using the correct formula? Thanks.
 
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No. mr^2 is correct for a cylindrical shell. Your disk is solid. Why don't you look up the correct formula?
 
You know what DICK? I am studying physics for the 1st time and I am working very hard at it so I would appreciate a little courtesy for those of us who "aren't as smart as you"
 
Apologies for being direct, but look. If you think you might have the wrong formula, you might try to look up the formula for the MOMENT OF INERTIA OF A DISK. Is that too much to ask? Geez. Aren't you being a little quick to take offense? Do you expect me to just tell you the answer? Then you are asking too much.
 
I apologize for jumping to offense. I just get frustrated with all of this and it takes me a while to understand some of the problems.

Thanks for helping out.
 
That's ok. I understand people get stressed with unfamiliar material and sometimes I see the answer as far more obvious than they do. You did get it right?
 
Yes, I got it. Thanks again.
 

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