1. PF Contest - Win "Conquering the Physics GRE" book! Click Here to Enter
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

B Energy expended during magnetic levitation?

  1. Mar 23, 2016 #1
    Two magnets, like poles facing, will "levitate". And they seem happy to do that forever.

    In common experience, it takes energy to jump, an airplane to generate thrust to convert to lift, or a helicopter to hover. "Hovering" for the local TV newscopter, or a SpaceX rocket is an energy intensive endeavor. Two doughnut shaped magnets on a stick, hovering, counteracts gravity like the helicopter, but unlike the helicopter does not "consume energy."

    In my case, my "everyday experience" is interfering with my ability to consider the problem without bias..

    Can someone set me on the proper track? What am I overlooking?
  2. jcsd
  3. Mar 23, 2016 #2


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

  4. Mar 23, 2016 #3
    Is this like a yogi that can levitate by standing on one leg, then folding up the other one? He does not move. When you say movement, how does that apply? to my question?
  5. Mar 23, 2016 #4


    User Avatar
    Staff Emeritus
    Science Advisor

    All those examples, other than the magnets, require that mass be accelerated, either in the form of expelled exhaust or air projected downwards. Magnets do not. Though that also means that permanent magnets cannot be used for propulsion.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted