How Do You Calculate Forces in a Truss Using the Method of Joints?

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To calculate forces in a truss using the method of joints, it's essential to first determine the reaction forces at the supports, which have been identified as -500 lbf at points A and C. The truss structure consists of triangles with 45° angles, but there is confusion regarding the number of members and the meaning of the lbf values. The method involves applying equilibrium equations, specifically Efx=0, Efy=0, and Em=0, to solve for the forces in each member. Clarification is needed on the configuration of the truss, particularly regarding the support at point B and the locations of points A and C. Understanding these elements is crucial for accurately calculating the forces in the truss.
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Homework Statement



i am trying to figure out the forces of the different members of this truss in which looks like a a square that is split into two triangles and is affixed to another triangle the same size I have already found the moment of the reactions and already found the reaction forces as well.

Code:
  A -500lbf  C -500lbf

                              2ft           2ft
                            --------l----------- l Pin Reaction E
                              \         l          /     l
                                \       l        /       l   2ft
                                  \     l      /         l
                                    \   l    /           l
                                      \ l  /---------l Roller reaction D
                                        B

Homework Equations


sin
cos
tan
Efx=0
Efy=0
Em=0

The Attempt at a Solution


more or less it is a question about the method of joints but I am not exactly sure how you do it. Also the triangles are all 45° 45° and 90°
 
Last edited:
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It is not clear, is your truss is made of 4 straight pieces, or 7? To what do the lbf refer?

If you wish to use ASCII art (and I don't recommend it), then you must include it within [code] [/code] pair. Otherwise the forum software squashes strings of spaces into a single space. You'll find it easiest if you also use Courier fixed-size font.
Code:
 [font="courier new"]
                       |
-----------------------|
\          |          /|
  \        |        /  |
    \      |      /    |
      \    |    /      |
        \  |  /        |
          \|/          |
-----------------------'
                                   [/font]
 
thank you and your picture is pretty much accurate without that line extending after B though
 
Point B is unsupported and in mid-air, is it?

What and where are points A and C?
 
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