1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Statics: Analysis of a Frame

  1. Jul 26, 2013 #1
    1. The problem statement, all variables and given/known data
    pErlIgy.png


    2. Relevant equations
    ƩFx=0
    ƩFy=0
    ƩM=0


    3. The attempt at a solution

    For the entire frame:
    ƩMA = 0: -360*15 -240*33 + E*12 = 0
    E = 1110 lb →
    ƩFx = 0: 1110 - Ax = 0
    Ax = 1110 lb ←
    These are the correct values so far.

    Member BC:
    W0a04tA.png

    By = (4/3)*Bx

    ƩMC=0: -240*9 + 360*9 + Bx*12 - (4/3)*Bx*18 = 0
    Bx = 90 lb
    By = (4/3)*90 = 120 lb

    These values are incorrect.
     
  2. jcsd
  3. Jul 26, 2013 #2

    TSny

    User Avatar
    Homework Helper
    Gold Member

    Does the force at B necessarily act along the member as you have assumed?
     
  4. Jul 26, 2013 #3
    Hmm I guess it doesn't.
    But I can't find another way of doing the problem. Every member seems to have 4 unknowns when isolated.
     
  5. Jul 26, 2013 #4

    TSny

    User Avatar
    Homework Helper
    Gold Member

    What can you learn from CDE?
     
  6. Jul 27, 2013 #5
    Ah, I figured it out now, thanks!

    I only need the value of Dx so I summed the moments about C.
    Then I solved for the three unknowns left on ABD.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted