1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Magnetic calculation

  1. Jun 2, 2007 #1
    i just joined this forum and it looks to be very very useful, particularly on the tests that i am about to commence, i have a question i need answering and i hope some one can, i need to calculate how large a magnet i would need to support the weight of a human being, i am looking to use neodymium permanent magnets at grade n52 for the initial testing, the weight needed to be supported will be about 140-160llbs, being a complete dolt as far as physics goes i thought i would turn to those who can do this in their sleep, hope you can help
  2. jcsd
  3. Jun 2, 2007 #2
    absolutely humongous, i don't think there are permanent magnets that big. i know that at the high field magnet lab at fsu they have the highest field magnet 45T and it could lift a frog and it is two stories tall
  4. Jun 3, 2007 #3

    Wel that answers my question i guess
  5. Jun 3, 2007 #4

    Meir Achuz

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    The force between two identical flat faced magnets of cross-section A and strength M (in gauss) is given by F=2pi M^2 A, which should equal mg.
    Put in some numbers.
  6. Jun 4, 2007 #5
    Thankyou meir

    Thankyou for the equation but the problem is you might as well have told me the way to the local 7 eleven in chinese, i really have no working knowledge of physics, all i have is my ideas, so to further enlighten you as much as i can heres what i am attempting to do, i believe i have found a way to make a hoverboard simalar to those used in back to the future, dont worry my next project isnt going to be self tieing shoes, but ist not a hoverboard in as such it is completely free floating, even i know i would need a lot more than that, such as a good special effects team and a decent camera man, but i do believe i have the next best thing, and i think that with 12-16 super magnets(i found these on the united nuclear website, and they are the biggest i have seen for sale to date http://www.unitednuclear.com/magnets.htm) i believe that a human beings weight can be supported, i am not looking to lift a person, just allow them to stand on a board the is being levitated by its repulsive field, if i can achieve stable equilibrium then the next phase will go into testing, but for now if someone could have a look at these super magnets and tell me if they are worth purchasing and if the number i plan to purchase will be sufficient.
    i cannot thankyou enough fopr the help
  7. Jun 16, 2007 #6
    why use magnet to do waht you have in mind, when compressed air can do the same job even better, like a hovercraft.. and regarding the answer that in order to lift a human being one would need a magnet as big as a house, well that may be true to just about everyone, but i am working on something like this and well have a look and you see waht i mean
    www.myspace.com/mfescience[/URL] thanks
    Last edited by a moderator: Apr 22, 2017
  8. Jun 16, 2007 #7
    p.s. please, please bear in mind that magnet are pretty powerful even those that are no biger than your palm, specialy when they are together with one another, .. so always take extreme care and keep away well away other metal objects, to stop accidently.hmmm you know...lol
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook