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

Magnets and gravity

  1. Sep 26, 2005 #1
    is it posible to make a magnet rotate around a center point, with the use of other magnets?
  2. jcsd
  3. Sep 26, 2005 #2


    User Avatar

    Staff: Mentor

    Electric motors do that. Or do you mean fixed magnets? If you mean by fixing magnets to an apparatus at specific angles to make another magnet spin, no, it can't be done.
  4. Sep 26, 2005 #3
    Do you mean to ask if it is possible to have a magnet orbit another magnet as the Moon orbits the Earth?

    If so, I don't think that it is possible without magnetic monopoles.
  5. Sep 27, 2005 #4
    you can place the magnets how you want, use anything you want, eg, string tieing up a magnet, whilt there is a magnet in the center, and yes i do want to make a magnet orbit anouther magnet or object.... like the moon orbits the earth
  6. Sep 27, 2005 #5
    The moon does not exactly orbit the earth, they orbit each other or I guess more properly, a common center of mass.

    If you mean that you want to say balance the repulsive force of two magnets with some force or forces acting in the opposite direction, yes, you just have to engineer that situation.

    But without some force other than their repulsive force (or attractive if you go the other way) you won't create an orbit, perhaps tying two magnets together on a stinger will create some straight line relationship but then an orbit requires more than that.
  7. Sep 27, 2005 #6


    User Avatar
    Gold Member

    Isn't he askeing if the tangential force would cancel the attractive force, just like a gravitational orbit? Could you not set two magnets in "magnetic orbit" around each other?

    Let's see, you would have to restrict their motion to a plane so that you could eliminate the dipole problem.

    Now, magnets attract as the cube of their separation, right? And you'd have the poles acting at both ends (N-S on top and S-N on the bottom), so your force would be 2r^3.

    Still, you should be able to (in theory) impart enough velocity upon them to cancel the attractive force, putting them in orbit about each other.

    Of course, it would be much more unstable than a gravitational orbit, since any perturbations are cubed rather than squared.
  8. Sep 28, 2005 #7
    how could i make and object float and spin by them selves, using magnets, or even just float.
  9. Sep 28, 2005 #8


    User Avatar
    Staff Emeritus
    Science Advisor
    Education Advisor

    You haven't heard about Maglev, or even seen those too-popular demonstration of superconductors levitating in magnetic fields?

  10. Sep 28, 2005 #9


    User Avatar
    Gold Member

    You should know that you won't be able to get magnets to do "work". You can impart energy to the system (just like you could start a pail of water on a string swinging around your head) but it won't do it on its own. Magnets are not a source of energy.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?