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Magnetic Pull/Repelling force of magnets?

  1. Jun 2, 2012 #1
    Hi all,

    I bought these neodymium magnets that all have a pull force of: 20.86 lbs
    If the pull force is equaled to that will the repelling force be the same as well? Since their both the same.
  2. jcsd
  3. Jun 3, 2012 #2
    No, your repelling force, meaning you face like poles at each other, you will then realize a much stronger repell. Your reference to the strenght of the magnet is its approx. lifting capability. The strength that it repels or attracks is measured in gauss.
  4. Jun 4, 2012 #3
    So the repelling force would be more stronger then the pull force? This magnets rated at 4600 gauss.

    I contacted my manufacture and asked him about the repelling force/ attraction force this is what they replied: "The Surface Field numbers listed for these magnets tells you the field strength right at the surface of the magnet.

    The attractive or repulsive force you get from these magnets depends on a number of factors, including field strength, and the overall size and shape. If you are interested in comparing the pull forces (or repulsion forces) of various magnets, compare the listed Pull Force, Case 1 numbers."

    I have two kinds of magnets one small and a larger one, each having a different pull force.

    One has about 5 lb's of pull force case1
    the large one has 20 lb's of pull force case 1 , the larger one is 4 times stronger and 3 times larger then the smaller one if the pull force is rated that why wouldn't the repulsion force do the same?
  5. Jun 4, 2012 #4
    My quick answer to that would be. The manufacture implies that there are mitigating circumstances in volved in measuring the pull/push strengths.

    Compare in your minds eye case1. Pull sm mag up against gravity to pulling sm mag with gravity. I would infer that the 'relative strength'/pull to each magnet is unchanged, the same. And I'd imagine that the pull strength at your location/your hand, would feel the difference. Ok maybe not your hand but a scale of sorts. ie non-ferrous fish weigh scale. Or even a pair of pall-point pen springs and see how far they comparatively stretch.
  6. Jun 7, 2012 #5
    I sent them an email asking them this:

    "Finally, is the attraction force or "pull case force 1" that is 20.5lb the same as the repulsion force? I mean are the attraction force of the magnets equal to te repulsion force?"

    Their reply:"Theoretically, yes, you can expect the attraction force between two magnets to be about equal to the repulsion force. In practice, the repulsion force you might measure is usually a bit lower, since any off-axis displacement means lower forces."

    Thats pretty good for me :smile: Having them at least equal to each other is fine, but thanks for all that help so far.
  7. Jun 29, 2012 #6
    An update about this topic:

    The rate of magnet's pull/repel forces varies under certain conditions and orientations. Its not a constant value like for example their mass.
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