1. Limited time only! Sign up for a free 30min personal 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!

Homework Help: Engineering statics: Truss Analysis Question

  1. Jul 12, 2015 #1
    1. The problem statement, all variables and given/known data

    So I was working on this problem, and my only questions are wether BE and CE can be assumed to be no force members? Also if I am not sure a member is a no force member, will it be revealed once I do the calculations,

    2. Relevant equations

    ΣF = 0

    3. The attempt at a solution

    I just need clarification on my questions, I can do the rest .


    Attached Files:

  2. jcsd
  3. Jul 12, 2015 #2
    Remember the rules which apply to zero force members. These are:

    1. If a joint contains three members with no external forces and two of the members are collinear with the third member connected from the joint, then the third member has an internal force of zero.
    2. If two members aren't collinear and there are no supports or external forces acting on the joint connecting these members, then both members have an internal force of zero.
    3. If two collinear members are connected by a joint and one member is known to have an internal force of zero, then the other member also has an internal force of zero.

    With this in my mind, are members BE and CE zero force members?
  4. Jul 12, 2015 #3
    Well rule 1 appies to both BE and CE so I am going to say they are?
  5. Jul 12, 2015 #4
    Joint C has a force of 500 lbs acting on it, it can't be a zero force member.
  6. Jul 12, 2015 #5
    oh yes makes sense, but but BE is, correct?
  7. Jul 12, 2015 #6
    Ok so when I calculate it I am getting a really small number for CE which is leading me to think it is a zero force member.
  8. Jul 12, 2015 #7
    Honestly, I'm not sure. The way I would do it is just try and resolve the forces in the members. If BE is a zero force member, then you can calculate it to have a force of zero.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted