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!

Statics - Finding Tension

  1. Feb 4, 2015 #1
    1. The problem statement, all variables and given/known data


    35197w2.jpg
    2. Relevant equations

    The answer in the back on the book shows 4.06i -7.61j + 5.07k. I do not understand why my signs are backwards.


    3. The attempt at a solution

    w1uwlv.jpg

    I ended with -4.06i +7.61j - 5.07k
     
  2. jcsd
  3. Feb 4, 2015 #2

    gneill

    User Avatar

    Staff: Mentor

    The tension involved is a vector that points from B towards A. You've created a vector rab that points from A to B.
     
  4. Feb 4, 2015 #3
    ok thank you. Since i did not see an arrow i was not sure which direction to pick. How did you tell?
     
  5. Feb 4, 2015 #4

    gneill

    User Avatar

    Staff: Mentor

    It's difficult to push with a cable :)
     
  6. Feb 4, 2015 #5

    That is a good point. Thank you
     
  7. Feb 4, 2015 #6
    Additionally, there is a weight pulling the boom downwards (or in the negative z-direction). In order to counteract this, the cable needs to pull it upwards (positive z-direction).
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted



Similar Discussions: Statics - Finding Tension
Loading...