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Levitation possible?

  1. May 27, 2014 #1
    I was solving a static electricity/electric field problem and I came across with one saying earth has an electric field of roughly 150 N/C at the surface. The book also states that it's negative, direction is toward the center of earth's core.
    So from the equation of F=qE one can find easily the necessary charge needed to counter effect the gravity:
    mg=qE

    so for a 187 pond man the charge must be something like 5.5 C. I assume that means if "somehow" I could charge my body 5.5C negative, that would balance my weight and I could levitate.
    Is that correct? Is something missing with this picture?
     
  2. jcsd
  3. May 27, 2014 #2

    Vanadium 50

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    Yes. If you put 5.5C on your body, you would start discharging lightning bolts. The only thing levitating would be your ashes.
     
  4. May 27, 2014 #3
    Ok maybe not by producing with my own body but within a gadget or something, some sort of costume like Iron Man has.
    By the way and electric eel can produce about 100V without "levitating his ashes" so it's not that far-fetched idea.
     
  5. May 27, 2014 #4

    russ_watters

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    Volts? Volts aren't relevant here. What is relevant is the charge.

    5.5C would be the charge of a relatively small lightning bolt, but a lightning bolt nonetheless.
     
  6. May 27, 2014 #5

    sophiecentaur

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    100V for the eel but 1010V (shorthand of a vast amount) for the man to be charged with all those Coulombs. The two situations are not comparable.
     
  7. May 27, 2014 #6
    OK, I'm not sure if I understood correctly , you mean to say if a person or his suit would have a 5.5C of electric charge on it, it would create a lightning bolt , so it's impossible to control it?
    Is this due to air? electric charge that big can not be hold on a surface because en electric arc would form on air surround it and eventually jump around just like a natural lightning bolt would do?
    How about space ? would that work on space?
     
  8. May 27, 2014 #7

    UltrafastPED

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    The spark depends upon the breakdown voltage of the air or other insulator. There are formulas for varying air pressures - Paschen's Law: http://home.earthlink.net/~jimlux/hv/paschen.htm

    If you look carefully it involves the materials, the distances, and the voltages as well as pressure, temperature, and humidity.

    If you were to discharge 5 coulombs over a period of 1 millisecond the current running through your finger/foot/nose ... the body part where the discharge occurs ... will be 5,000 amps. The voltage from your height to the ground is the value 100 volts per meter; so assuming your belt buckle, the power is 5,000 amps x 100 volts = 50,000 watts for 1 millisecond.

    As was said earlier, this will be very bad for the affected body parts!

    Also see http://en.wikipedia.org/wiki/Atmospheric_electricity
     
  9. May 27, 2014 #8

    sophiecentaur

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    Forget the sparks. Just consider the coulomb force needed to keep 5.5C of charge within the space occupied by a man. Two charges of 2.5C each, separated by a metre (i.e. two halves of your man) would experience a repulsive force of around 1012N. Your experimenter would fly to pieces long before he managed to get a fraction of that amount of charge on him.
     
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