Is the Sum of All Moments Zero at Any Point if Zero at Point A in 2-D Mechanics?

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The discussion revolves around the concept of moments in 2-D mechanics, specifically whether the sum of all moments being zero at a point A implies it is zero at other points on the body.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants explore the relationship between moments and equilibrium, questioning whether zero moments at one point guarantee zero moments elsewhere. Some express uncertainty about the implications of finding both resultant force and moment equal to zero.

Discussion Status

The discussion is ongoing, with various interpretations being explored. Some participants suggest that the conditions for equilibrium may not be fully understood, while others provide insights into the dependency on specific problem details.

Contextual Notes

There are indications of confusion regarding the definitions of equilibrium and moments, as well as concerns about the appropriateness of posting the same question in multiple forums.

kasse
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If the sum of all moments about a point A of a body is 0, will it then be 0 anywhere else on the body? (I'm working in 2-D)
 
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Maybe. It depends entirely on the particulars of the problem.
 
Not necessarily.
 
So I don't necesarrily have equilibrium if I find that F(res) = 0 and that M(A) = 0 ? What more do I need to `show eq.?
 
I assume that it works the other way around: if I know that there's equilibrium, then the sum of all moments around any point is 0.
 
kasse said:
I assume that it works the other way around: if I know that there's equilibrium, then the sum of all moments around any point is 0.
That is correct. With respect to your previous post, it depends on the situation, as Russ said in your other thread.
 
kasse said:
If the sum of all moments about a point A of a body is 0, will it then be 0 anywhere else on the body? (I'm working in 2-D)

kasse, do not multiple post the same question across multiple forums. I've merged in the thread that you started in Classical Physics with the same question.
 

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