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Physics project: Self propelled car.

  1. Jan 6, 2009 #1
    ok, so i have a physics project. we were assigned to use a mouse trap tied to the axle by a string to propel a homemade car of sorts. but he says we can use and propulsion system as long as it doesn't use combustion or electricity. i don't wanna use a mouse trap and i'm looking for other ideas. maybe magnetic? any ideas? we also are to design a braking system so that the car will stop at a self-set distance such as 40m. any ideas?
  2. jcsd
  3. Jan 6, 2009 #2


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    For all the years I've been here, this is a problem that seems to come back once or twice a year. Do some searching with the search tool on this forum...
  4. Jan 7, 2009 #3
    i have searched and all of them use mouse/rat traps that pull a chord attached to the axle. im looking for a different source of thrust/propulsion...
  5. Jan 7, 2009 #4
    Try compressed air. Rip apart one of those air hogs planes and just the power plant to drive your mouse car instead of a propeller.
  6. Jan 7, 2009 #5
    Air hogs planes are pretty expensive if you don't use them for what they are meant for! Instead, I would suggest using a spray can (the ones that clean computers and stuff) and have the axle trigger it somehow, like someone pulling a string.
  7. Jan 7, 2009 #6
    shoulda said this earlier... no compressed air or water. =( :grumpy:
  8. Jan 8, 2009 #7


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    Mmm, no springs (mousetraps), no compressed air, no water, no electricity, no combustion...

    It's going to become difficult to find an energy storage. I have a proposal: use nuclear fusion :biggrin:

    Can you use chemical reactions other than combustion ?
    Or use a sail ? Can you use an animal ?
  9. Jan 8, 2009 #8
    i can use a sail! and i can use springs(mousetraps). but i was trying to stay clear of the cliched mousetrap. i can use magnets somehow. no animals though. and i need a braking system :mad::grumpy:
  10. Jan 8, 2009 #9
    Maybe use a flywheel?
  11. Jan 8, 2009 #10
    explain this flywheel method???
  12. Jan 8, 2009 #11
    It's basically just a rotating mass (see http://en.wikipedia.org/wiki/Flywheel), there are also some toy cars that use them (like http://www.madcattoys.com/cu1027kk.html).

    The toy starts driving right away after charging it (by moving the toy) but you could make an alternative way to charge it with a lever or something. And could decouple the flywheel to be able to switch it on later instead of right away.

    Not sure how long it'll hold it's energy due to friction though, never tried it myself ;)
  13. Jan 8, 2009 #12
    im totally going to try it
  14. Jan 8, 2009 #13
    wait how can i build/get a flywheel
  15. Jan 8, 2009 #14
    You could pull one out of any of these toys http://gyroscope.com/, but I think pretty much any (heavy) disc would do. But I don't know any of the math involved ;)

    Upside of those is also they come with starter wires ;)
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