Help with summing the moments in statics

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Discussion Overview

The discussion revolves around a homework problem related to summing moments in statics, specifically at points A and B. Participants are attempting to reconcile differing results obtained from summing moments at these two points.

Discussion Character

  • Homework-related, Mathematical reasoning, Debate/contested

Main Points Raised

  • One participant expresses confusion over differing results when summing moments at points A and B, indicating that the calculations do not yield consistent values.
  • Another participant points out a potential error in the labeling of variables, suggesting that a term should be referred to as rah instead of rbh.
  • A further contribution emphasizes that the sum of horizontal forces must account for all horizontal components, suggesting that this principle is independent of the point chosen for summing moments.
  • Participants mention the need to consider the sum of all vertical forces as another equation to analyze the problem.

Areas of Agreement / Disagreement

There is no consensus on the correct approach or resolution of the discrepancies in the calculations. Multiple competing views and interpretations of the problem remain present.

Contextual Notes

Participants have not resolved the assumptions underlying their calculations, and there may be missing definitions or steps in the mathematical reasoning presented.

thekrustyone
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Homework Statement


I need to sum the moments on a and b but when i sum them at b the number I get doesn't work when I check and sum them at a.

Homework Equations

The Attempt at a Solution

 

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(-200x4)+(-60x2.5)+(-60x2.5)+(rbhx10)=rbh=110

(200x6)+(-60x2.5)+(-60x2.5)+(rahx10)=-90

Sum horz=0=110+200+rah if moments summed at A
Rah=-310

Sum horz=0=-90+200+rbh if moments summed at B
Rbh=-110

Why are they not the same I don't understand
 
thekrustyone said:
(-200x4)+(-60x2.5)+(-60x2.5)+(rbhx10)=rbh=110
Should be rah
 
thekrustyone said:
Sum horz=0=110+200+rah if moments summed at A
The sum of the horizontal forces must be the sum of ALL horizontal forces. There are 3 forces with horizontal components. This sum equals zero and has nothing to do with the point about which you choose to sum moments.

Another forces equation can be obtained by setting the sum of ALL vertical forces = 0
 

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