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HELP! Trying to Make a Spring Car No Mouse Traps!

  1. Mar 12, 2009 #1
    I am a senior in High School, I have been given a 3" X 1/2" compression spring that must power a car. This is not a mouse trap powered car, (that was last year). I need help trying to determine high to harness the extreme energy stored in this heavy spring and somehow get a car to travel the farthest. In the mouse trap car it was very easy I simply used a rod long enough to slowly release the energy over a long time period. With this spring I would need a 2X4 attached to wheels. I have tried to attach a small fish line to the spring and then around the axle, but there is so much pressure when the spring is compressed that it does not wrap around the axle. I have tried wire, wax string rubber coated string, I just think that variation will not work, I need some other input. Thank you Nate!
  2. jcsd
  3. Mar 12, 2009 #2


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    Science Advisor
    Gold Member

    Try using a lever on the spring to reduce the force then use string on end of lever wrapped around an axle.

    There are four basic machines I can think of which can trade off force vs. distance of travel.
    The lever
    The pulley
    The inclined plane or wedge
    and systems of pistons pneumatic or hydrolic.

    I would guess a piston system is too complex for your application.
    I would think a wedge system would have too much friction for your application. These are better for increasing forces.
    This leaves levers and pulleys and I think you'll find some combination is best.

    I would also suggest you try thinking of the problem in reverse... how to compress or stretch that spring by rolling your car. This may help you visualize different possible configurations.
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