Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

I have a question about pulley

  1. Sep 11, 2012 #1
    Hi

    I have a question about pulley.
    There is fixed pulley: http://en.wikipedia.org/wiki/File:Polea-simple-fija.jpg http://en.wikipedia.org/wiki/File:Polea-simple-fija.jpg where you need to use e.g. 100N to lift 100N.
    There is moveable pulley: http://en.wikipedia.org/wiki/File:Pulley1a.svg http://en.wikipedia.org/wiki/File:Pulley1a.svg where you need to use e.g. 50N to lift 100N.

    Question: How does "reversed moveable" pulley look like, i.e. the one where I need to use 200N to lift 100N? I need it for my home gym.

    Thanks
    Adam
     
  2. jcsd
  3. Sep 11, 2012 #2

    K^2

    User Avatar
    Science Advisor

    Re: pulley

    On the image for moving pulley, picture weight hanging from the free end of the rope instead of from the moving pulley. It will take 200N of downward force on the moving pulley to lift the 100N weight in that case.
     
  4. Sep 11, 2012 #3
    Google images for a block and tackle, or a mobile crane block. Once you see one rigged up your answer should be self evident.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook