Why Is My Solution for Rotational Motion Incorrect?

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Homework Help Overview

The discussion revolves around a problem related to rotational motion, where the original poster is attempting to solve equations but encounters discrepancies in their results. They express uncertainty about their approach and seek clarification on their work.

Discussion Character

  • Exploratory, Assumption checking, Mathematical reasoning

Approaches and Questions Raised

  • The original poster shares their attempts to solve the equations and questions where they might have gone wrong. Participants point out specific algebraic mistakes, such as illegal cancellations in their calculations.

Discussion Status

The discussion includes acknowledgment of mistakes and offers supportive comments regarding common errors in algebra. Participants are engaging in clarifying the original poster's approach without reaching a definitive resolution.

Contextual Notes

The original poster has provided attachments for their work, indicating that there may be additional context or details that are not fully visible in the thread itself.

GreenPrint
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Homework Statement



Please see the attachment.

Homework Equations





The Attempt at a Solution



Please see the attachment. When I tried to solve the equations for a I got a different answer and I don't see what I'm doing wrong. Please let me know if you cannot follow my work. Thanks for any help you can provide.
 

Attachments

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Illegal algebra cancellation.

[tex]\frac{MR^2}{2}\frac{a}{r}=(F_T)\,r[/tex]

In the above equation, you canceled r on the left side with r on the right side.
 
oh that's embarrassing thanks
 
GreenPrint said:
oh that's embarrassing thanks

Don't be embarrassed by it. Arithmetic and algebraic mistakes just plumb happen even to the best of us. I've had a professor who was the chair of my university's physics department and who performs nuclear physics experiments (specifically with lead nuclei, IIRC) at the LHC, and on occasion he made algebra errors when demonstrating examples on the board. Just go through stuff more slowly and carefully, and you should minimize the number of those mistakes that you make. :)
 

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