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 in a Rope

  1. Mar 31, 2010 #1
    Sorry I deleted the template, it doesn't seem to apply much to this particular problem:

    A professional strongman ties rope A to a building and pulls as hard as he can on the rope. Two other professional strongmen take either end of rope B and pull in opposite directions as hard as they can. If all strongmen possess equal strength, how do the tensions in the rope compare?

    It's a multiple choice question and the answer listed is: The ropes have the same tension.

    This just doesn't seem correct to me, could anyone enlighten me or confirm my doubts? As I see it, if all the strongmen pull with a force of 10N (perhaps we should call these strongmice instead), then clearly rope A would have a tension of 10N, while rope B would have a tension of 20N.
  2. jcsd
  3. Mar 31, 2010 #2


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    Not as clearly as you think. Just imagine that the wall is a strongman. Whether a strongman or a wall, either would exert the same force on the rope...10N. That's Newton 3. You might want to cut a section thru the rope and draw a Free Body diagram around one of the strongmen, and use newton 1 for equilibrium.
  4. Mar 31, 2010 #3
    Thanks for the help, that's just a weird thing to conceptualize.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook