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: Tension on a String

  1. Apr 2, 2007 #1
    I'm trying to figure out the sag of a wire hanging between two objects. If I string a wire between two structures and tension the wire 5000 lbs in the horizontal direction, I can estimate the shape of the wire to be parabolic and use the equation: Sag = (W*L^2)/(8*T), where W=Weight of wire, L=Span between two supports, and T=Horizontal Tension to calculate the sag. If now I add a much heavier wire to the first wire, how can I arrive at the new Sag and Tension for the two wire combination? I am assuming the same temperature for both installations (60 degrees F). The first wire is .65 lbs/ft; the second wire is 7.8 lbs/ft. I am trying to solve the problem without neglecting the initial wire's weight.

    Attached Files:

    Last edited: Apr 2, 2007
  2. jcsd
  3. Apr 2, 2007 #2


    User Avatar
    Gold Member

    Have a look at this


    If two different wires hang in the same curve they must be joined along their length, so you can pretend it's one wire with the average density (?)
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook