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!

Hanging Sign, Tension

  1. Dec 13, 2011 #1
    A purple beam is hinged to a wall to hold up a blue sign. The beam has a mass of mb = 6.2 kg and the sign has a mass of ms = 15.1 kg. The length of the beam is L = 2.78 m. The sign is attached at the very end of the beam, but the horizontal wire holding up the beam is attached 2/3 of the way to the end of the beam. The angle the wire makes with the beam is θ = 30.6°.

    What is the tension in the wire?

    I have set the torques of the beam's weight and the sign's weight equal to the tension torque as follows:
    (6.2)(9.8)(.5)(2.78)(cos30.6) + (15.1)(9.8)(2.78)(cos30.6) = (T/sin30.6)(2/3)(2.78)

    Solving for T, I keep getting 117 N which is not the right answer...
    Could anyone explain where I am going wrong?

    Attached Files:

    Last edited: Dec 13, 2011
  2. jcsd
  3. Dec 13, 2011 #2
    Replace '/' by 'times'
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook