Electro Magnet Gun

in General Discussion edited January 2014
I need to build a catapult for my physics class and besides doing it the regular way I had some questions about making one that propelled a platform to shoot the object with electro magnets.

I need to shoot a bouncy ball 3 feet into a 32oz cup simply put. I just have some questions.

How hard would it be? How much would it cost? How much electricity would I need? How hard is it to build a delay circuit for tenths?maybe less of a second? Is it worth even trying? IF all this is possible, how hard would it be to put some sort of adjustment dial on it so I could control how far it shot?

I figure I?ll build a regular one too, but this would just be neat and I could win some bonus points if it worked


  • Reply 1 of 6
    What you are talking about sounds a bit like what is commonly referred to as a rail gun (or Gauss gun).

    http://en.wikipedia.org/wiki/Rail_gun has some links to pages that show how to build a working model. You could probably adapt a design for your catapult. Might be more work than just making a regular catapult.
  • Reply 2 of 6
    Maybe you could make a Trebuchet?
  • Reply 3 of 6
    splinemodelsplinemodel Posts: 7,311member
    I'm not quite sure how you could propel a non-magnetic projectile with electro magnets, but anyway. . .

    There are so many ways to do this. I'd recommend pressurized gas because it's so easy to fine tune the initial velocity (depends on pressure) AND it's very easy to aim. It would take some amount of part scavenging and a tube of KY, but all in all it's a far more mechanically simple (read: reliable and easy) device than any sort of catapult.

    Plus, you'll learn about pressure instead of spring constants and torque, which are more simple to figure out from a book.
  • Reply 4 of 6
    billybobskybillybobsky Posts: 1,914member
    the less moving parts the better...

    so go with air pressue...
  • Reply 5 of 6
    randycat99randycat99 Posts: 1,919member
    I agree that compressed air would probably be the most straightforward. However, if you are still holding out for that fancy EM solution, you could always try using a woofer loudspeaker, a signal generator, and amplifier as a basis for propulsion. Alternately, you could ditch the signal generator and amplifier, and just use a hefty DC power supply that has a voltage adjustment.
  • Reply 6 of 6
    ast3r3xast3r3x Posts: 5,012member
    Well I've never worked with gases before so I'm not sure I could do that..safely or inexpensively. I was hoping to use regular wall outlet...using a subwoofer is a good ideas. Think that would be powerful enough? I'm not sure where I would get that though...not like I have extra's laying around.
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