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Homework Help: Truss Analysis

  1. Nov 17, 2008 #1
    1. The problem statement, all variables and given/known data
    Determine the forces in each member of the truss shown. Also find the values for any reactant forces

    http://img201.imageshack.us/img201/6853/trussnu9.jpg [Broken]

    2. Relevant equations

    Fx= 0
    Fy= 0

    3. The attempt at a solution

    I set θ in the corner of J1
    tan θ=12/16
    θ = tan-1 12/16
    θ = 36.87

    I set Φ in the corner of J3
    tan Φ = 12/9
    Φ = tan-1 12/9
    Φ = 53.13

    This is where I began to falter. I could not figure out how to diagram everything out. If someone could just at least give me a diagram of where things are supposed to go, I can sum up the x and y forces by myself. This is pretty urgent, and I was absent for this class so my only help is messy notes from another student. This isn't in my textbook. Any help will be appreciated.
    Last edited by a moderator: May 3, 2017
  2. jcsd
  3. Nov 17, 2008 #2
    You want to resolve the forces. If a force [tex]F[/tex] makes an angle [tex]\theta[/tex] with the horizontal, the horizontal force is [tex]F_x=Fcos\theta[/tex] and the vertical force is [tex]F_y=Fsin\theta[/tex].

    Give us something to work on and we'll lead you on.
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