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

Magnetic Rotation

  1. Jul 4, 2015 #1
    If I have a magnetic setup in frictionless, etc. area as follows:

    N
    /
    /
    /
    ---------------------S

    Will the "south" pole rotate up to the "north" pole, causing the system as a whole to rotate?
     
  2. jcsd
  3. Jul 4, 2015 #2

    A.T.

    User Avatar
    Science Advisor
    Gold Member

    Why not the other way around?
     
  4. Jul 4, 2015 #3
    It is my understanding (and it has been awhile since magnetics in college) that it would rotate toward "north" - like a compass. But for sure I would like to be able to control the direction of rotation...
     
  5. Jul 4, 2015 #4

    A.T.

    User Avatar
    Science Advisor
    Gold Member

    Are the vertical and horizontal bars free to rotate relative to each other, like the compass needle can rotate relative the Earth? If, yes do they have the same mass ratio as the a compass needle and the Earth?
     
  6. Jul 4, 2015 #5
    It is all connected. Ultimately, it is a full cross shape that I am trying to rotate about the center.
     
  7. Jul 5, 2015 #6
    This is operating in a frictionless environment. Each bar is the same mass, and like I said there are four making a complete cross. I am trying to see if the whole thing will start rotating about the center as the "south pole" is attracted to the "north pole".
     
  8. Jul 5, 2015 #7

    Drakkith

    User Avatar

    Staff: Mentor

    So you've effectively taken two bar magnets and put on on top of the other, offsetting one by 90 degrees?
     
  9. Jul 5, 2015 #8

    Dale

    Staff: Mentor

    No. An internal force cannot cause a net torque.

    We don't discuss perpetual motion machines here. Thread closed.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook