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!

Tensions equilibrium

  1. Apr 27, 2014 #1
    1. The problem statement, all variables and given/known data
    see pic


    2. Relevant equations



    3. The attempt at a solution
    Ive worked out T1 which is T1=F1(-4i-5j-10k/11.8743) = T1(-0.337i-0.421j-0.842k)
    and T2=F2(-4i-5j-10k/11.8743) =T2(0.337i-0.421j-0.842k)
    and the next step is to find the unit vector of force M = 20kn but how do i work out unit vectors from the diagram if the lengths aren't given?

    (the answer given is 6.84i + 18.794j for the unit vector of M=20kN but how??)
     

    Attached Files:

    Last edited: Apr 27, 2014
  2. jcsd
  3. Apr 27, 2014 #2

    SteamKing

    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper

    You obviously don't realize that a 'unit vector' has a magnitude = 1, which is why it's called a unit vector.

    You know the magnitude of the force M (which = 20 kN) and you are shown the direction of the M vector in the diagram. The M-vector is parallel to the x-y plane and it makes an angle of 20 degrees with the positive y-axis. Ergo, you can work out the components of M using simple trigonometry.
     
  4. Apr 28, 2014 #3
    oh i get it now thanks
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted