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Repulsive force question

  1. Jan 11, 2010 #1
    Hello. I'm new to the forum and I hope this is the correct place for this question. Would it be possible to lift a 200,000 lb rectangular object that is in motion using rare earth permanent magnets at each corner?
  2. jcsd
  3. Jan 11, 2010 #2
    Yes. Place a magnet under each corner and lift away.
  4. Jan 11, 2010 #3
    Rofl. Or get big enough magnets and lift from the top.
  5. Jan 11, 2010 #4
  6. Jan 13, 2010 #5
    Thanks Bob. I will check that out.
  7. Jan 18, 2010 #6
    Hi Bob, Thanks again for your response. I checked out the calculator. My next question, being that the calculator dealt with attractive force, is the repulsive force of a magnet equal to the attractive force of a magnet?
  8. Jan 18, 2010 #7
    The repulsive force of two same-polarity magnet poles is due to the spacial-derivative of the total magnetic energy (magnetic energy density integrated over all space):

    W = 1/2 ∫B·H dVvolume

    The force along x is then

    Fx = dW/dx

    This is the same force that attracts a magnet to a steel plate, at least it is calculated in a similar way.

    Bob S
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