Equal Moments at A: Reasoning and Calculation

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Homework Help Overview

The discussion revolves around the concept of equal moments about a point A, specifically examining the conditions under which two moments can be considered equal. The subject area pertains to rotational dynamics and torque calculations.

Discussion Character

  • Conceptual clarification, Mathematical reasoning, Assumption checking

Approaches and Questions Raised

  • Participants explore the use of the torque equation τ = rFsinθ and question the reasoning behind the equality of moments. There is an attempt to clarify the definitions and components involved in calculating torque.

Discussion Status

The discussion is active, with participants providing different interpretations of the torque equation and questioning the original reasoning. Some guidance has been offered regarding the correct application of the torque formula, but there is no explicit consensus on the reasoning presented.

Contextual Notes

Participants are navigating through potential misunderstandings of terminology and the application of the torque equation, indicating a need for clearer definitions and assumptions regarding the forces and angles involved.

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Homework Statement



Do the following have equal moments about A?

moment031.gif


moment032.gif


Homework Equations



T=rf

The Attempt at a Solution



Yes because using L*cos(30), they will be the same?


What is your reasoning?
 
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NoobeAtPhysics said:
Yes because using L*cos(30), they will be the same?

What is your reasoning?

Your reasoning is incorrect ...

τ = r×F

τ = rFsinθ

or τ = r times (component of force perpendicular to line joining A and point of application of force )

So what is τ ?
 
They both use τ = rFsin30 right? That means they are equal! Right?
 
Right...
 
Last edited:
NoobeAtPhysics said:
They both use τ = rFsin30 right? That means they are equal! Right?
"Use" is a strange word there. "Supply" perhaps. Anyway, you asked whether your reasoning was correct, and Tanya S was right in reply, that your reasoning was incorrect (though you got the right answer).
 

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