Finding Forces in Truss Members Using Method of Sections

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Homework Help Overview

The discussion revolves around determining the forces in members BC and CG of a truss structure, focusing on the method of sections. Participants are exploring the implications of their calculations and the assumptions made regarding angles and member forces.

Discussion Character

  • Exploratory, Assumption checking

Approaches and Questions Raised

  • Participants express uncertainty about their calculations, particularly regarding the angle θ and the identification of zero force members. There is mention of potential errors in reaction forces due to asymmetrical loading.

Discussion Status

The discussion is ongoing with participants sharing their attempts and questioning the validity of their approaches. Some guidance has been offered regarding the structure's loading conditions and the implications for their calculations.

Contextual Notes

There are indications of confusion regarding the calculations of reaction forces and the identification of zero force members, which may affect the overall analysis of the truss.

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Homework Statement


Determine the forces in members BC and CG. The forces are positive if in tension, negative if in compression.
20150715_190800_zpseupbftpt.jpg

Homework Equations


ΣF=0
ΣM=0

The Attempt at a Solution


20150715_190729_zpszsi20agz.jpg

im not sure what I am doing wrong here, i think it might be my angle θ?
I got 3.66N tension as my answer but its wrong, i just started trusses and not sure what I am doing wrong.
 
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Im working on a similar problem and am making the same mistake, maybe CH needs to be found? but i think its a zero force member.
 
J-dizzal said:

Homework Statement


Determine the forces in members BC and CG. The forces are positive if in tension, negative if in compression.

Homework Equations


ΣF=0
ΣM=0

The Attempt at a Solution


20150715_190729_zpszsi20agz.jpg

im not sure what I am doing wrong here, i think it might be my angle θ?
I got 3.66N tension as my answer but its wrong, i just started trusses and not sure what I am doing wrong.
Your calculations appear to state that Ay = Fy = 14 (kN?)

The structure is not loaded symmetrically, so these reactions are incorrect.
 
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SteamKing said:
Your calculations appear to state that Ay = Fy = 14 (kN?)

The structure is not loaded symmetrically, so these reactions are incorrect.
thank you sir.
 

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