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Electromagnetic holding force to size of Magnet Ratio

  1. Jan 21, 2015 #1
    Hey all, I'm new here and hoping to enjoy glorious physics with you all!
    I have a problem and a question; the problem is I don't know much about electromagnets and want to build something rather involved using an electromagnet. XD
    The question shall be explained..
    General Concept:
    I'm going to build a semi-permanent wire swing; this swing shall be attached to a 2 inch thick steel plate by a small electromagnet; the steel plate permanently mounted to a tree. (imagine a wire with an electromagnet on one end affixed to a steel plate)
    I'm going to use mechanical means to toss the electromagnet at the steel plate trailing the wire; the wire and magnet need to be under one pound or I won't be able to propel it without an unrealistically large amount of force. The wire weighs nine onuses; that leaves seven onuses for the magnet. So my question is this: is it possible for a seven ounce electromagnet to hold 600 pounds; assuming there is no limit to the amount of electricity I can power the magnet with?

    Reason for 600 pounds...
    With safety in mind; If a 200 lbs man were to swing from a 90 degree angel; the most force the wire (and magnet) will be under is about three times the weight of the man; thus the 600 lbs.
     
  2. jcsd
  3. Jan 21, 2015 #2

    mfb

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    Staff: Mentor

    If the electromagnet is suppoed to hold the whole swing (with a passenger), where is the point in the strict weight requirement? Can you draw a sketch?
    US-units are weird, but I still think those specifications are hard to meet. It would be much easier with permanent magnets. There are geometries where you can rotate them to switch their external field on and off.
     
  4. Jan 21, 2015 #3
    It would be easier with permanent magnets? I was under the impression electromagnetic magnets were more powerful.
    Where is the point in the strict weight requirement? Do you mean what is the point in the struct weight requirement? As for where it is the most extra force is exerted at the point when the wire is vertical during the swing.
     
  5. Jan 22, 2015 #4

    mfb

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    Staff: Mentor

    For the same weight? No.
    They can give a higher peak magnetic field.

    I mean strict.
    I don't understand what you mean.

    Please give a sketch of the setup, that would really help to understand what you want to do with the magnet.
     
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