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Dispute this! (please?)

  1. Jul 21, 2004 #1
    Skip this if you dont care:

    Hello there my name is John. I have sent this email to several members of the Idaho Academy of Science in search of answers. I believe my idea may actaully be of some use to man kind in the future!

    First off let me say that I'm always pleased to meet & converse with other aspiringly great, or perhaps already great, but nonetheless still growing, minds. I'm 18 and I am currently enrolled at the UCF Computer Science program, and I am extremely excited about delving into math theory, algorithms, quantum cryptography, magnetism, astronomy, and many other branches of Science.

    OK now...

    My first question, I suppose, is about electromagnets, before I begin my search, googling of course; would anyone out there happen to be an expert in the field? (no pun inteneded).

    I'm looking for any equations about how much power is needed to be sent to an electromagnet to push another Neodymium (natural) magnet, using like poles while on a very very near-frictionless surface. Would it be possible to calculate the distance traveled, acceleration, and velocity of the Neodymium magnet when pushed by the electromagnet's magnetic field? Perhaps, also, how much current (or magnetic strength B) would be needed to power an electromagnet to stop a neodymium magnet of (B) strength, going (v) km/s toward the electromagnet (on..let's say..a very very very slick...ice type surface? (but not really ice of course)). And send the neodymium magnet in the opposite direction. All..perhaps...let's say for the sake of simplicity... in a very well made vaccum?

    Could there be an equation yet? I'm sure there is somewhere out there in Tesla's notes perhaps?! If you have questions, or would be interested in helping me, I'd very much appreciate the help! I apologize if my questions are jumbled and difficult to decipher!

    I believe that if I could just gather these equations, i would be well on my way to making...well...i dont want to be called crazy and people ignore me, so i will be prudent in disclosing my ideas :)

    But still I cannot help myself..

    What if...say instead of a magnet that was divided down the middle vertically with poles

    [ + | - ] <--- rectangular magnet - neodymium

    divided horizontally instead

    [----------] <----rectangular magnet - neodymium

    then by placing two more magnets on the top and bottom....

    [----------------------------------------] <----rectangular neodymium
    [----------] <----rectangular magnet - neodymium
    [-----------------------------------------] <----rectangular- neodymium

    Would not the smaller magnet in the middle remain suspended between the two larger magnet 'tracks'? if placed in a VERY well made vacuum, this would nearly imitate an object floating through space - if the tracks on the top and bottom were infinitely long - the magnet in the middle would float on forever, if it were not for a flawwed vaccum, or slight misalignment of the magnet track.... creating a nonuniform force field for the smaller magnet to float on, this eventually stopping it's movement...

    So my question is, in this field, are there equation that could help me determine how fast and how long the magnet would move? And how much current generated if passed through a coil?

    Yes I am aware of the mag-lev trains :)

    Infact that was my idea first! (when I was eight...)

    Hehe well perhaps i didnt have all the details worked out but...

    Would anyone happen to know the equation to calculate how much energy could be gained from a magnet of M mass with a Mag. field strength of B running at about 3 m/s?

    I believe the energy needed to propel a magnet with another electromagnet to 3 m/s would leave extra energy left over as the moving magnet induced curent into a wire, since the electromagnet would only need to move the magnet, then turn off. BEcause of the lack of friction, the magnet would continue to move, change, and create current. This would leave extra energy as it passed through a coil/iron core, some current used to Re-energize the system, and some used for excess energy. THen as the natural magnet moved , it would trip a switch to turn on another electromagnet on the other side which would in turn stop the magnet then push it the opposite direction. ONce the magnet was moving in the other direction, it would turn off the electromagnet and create excess energy.
    | | _________ | |
    | | | | | |
    | | | | | |
    | | |________| | |

    Imagine the magnet being pushed uniformly, taking gravity into account, from all sides...levitating with no friction (that i know of...remember this is in a vaccum, so nearly no air resistance) involved. The magnet being pushed form all sides would need to be, actaully, a Quad-pole magnet, or perhaps more, but it isnt hard to imagine a cube of magnets put together. On the left and right sides are electromagnets that, when the magnet comes near, are energized with enough current to create a magnetic field that would propell the magnet in the opposite direction. Some type of alternator, like the ones used in a car, could reenergize the electromagnet's energy supply.

    When the floating magnet is on it's way...nothing will impede it's path, according to newton's laws, and it will continue to move nearly forever, all the while passing through coil and creating current....this 'forever moving' possibility will allow the device to create enough energy to recharge the electromagnet, create excess energy, then do it all over again when it approaches the opposite side....

    Ping....Pong...Ping...Pong...forever...Bqv? BvL?

  2. jcsd
  3. Jul 21, 2004 #2
    Ah! I think the ammount of coil used would also effect this!

    So... 1 Tesla x 100 yards of wire x 3 m/s = 300 volts? will it take more then 300 volts to move a magnet with an electromagnet at 3 m/s? I think not...but perhaps im wrong but this means left over energy!
  4. Jul 21, 2004 #3
    OH and the diagram is all messed up :) oops...just read carefully and slowly, i will clear up any questions if need be
  5. Jul 21, 2004 #4
  6. Jul 21, 2004 #5
    a physicist is the atoms' way of thinking about atoms...anonymous wrote that :)

    Hmm...so...if I had...say.... 1000 turns of wire wrapped around with a Magnet passing through at 3 (or more) m/s, with a strength of 1 Tesla (or more...however high a large neodymium natural magnet can get..)


    what would the A be in delta (BA)/delta T be? Area? I dont know! My brain has difficulty with tese things...i cant help it!

  7. Jul 22, 2004 #6


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    Science Advisor
    Homework Helper

    You can't have the magnet create a current forever when no external forces are at work. This would be a violation of the convervation of energy.

    What happens is that when the magnet moves through the coils of the electromagnet and induces a current, there will be a changing magnetic field which induces an electric field directioned as to oppose the current. Therefore you will need a force to push your magnet along or it will come to a halt due to this back emf.
  8. Jul 23, 2004 #7
    WOw! I was just thinking that! I said to myself...I wonder if EMF would push back on the magnet as it passed through the coil. But this is irrelavent.

    I dont blame anyone for not reading the entire original post. But the entire device is about 6 meters long. I guess it's good that most people didnt read this or else my idea wouldnt be mine anymore lol!
  9. Jul 23, 2004 #8


    User Avatar

    Staff: Mentor

    Here is the problem:
    You don't understand what energy is (IIRC, that makes it a type 1 perpetual motion machine, ie, it breaks the 1st law of thermodynamics). Kinetic energy is 1/2 mv^2. That means if you take energy away from the moving magnet, you will reduce its speed. Eventually, it will stop.

    The energy you put into it will accelerate it to some speed. The energy you take out of it will decelerate it to a stop. These two energies are exactly the same - indeed, you can make a loop of your track (or better yet, a straight track with a spring at the end) and use the same coils to do the accelerating and decelerating.

    You may be interested in a common physics demonstration in college: a magnet is dropped down a non-magnetic, metal pipe. What happens? The magnet induces a current in the pipe (thousands of amps), making the magnet drop very slowly through the pipe.
    Last edited: Jul 23, 2004
  10. Jul 24, 2004 #9

    springs? goodness no....well perhaps as a saftey - but there are electromagnets on each side that push the natural magnet back and forth, through the coil. A photo-sensitive sensor turns off and on the electromagnet sto use like-poles to keep the magnet in motion, and generating more current than needed for a pulse of magnetic field.
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