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Design a wooden cart

  1. Dec 28, 2005 #1
    I am a junior in highschool working on a project in which you have to design a wooden cart with no padding to carry a egg one meter as fast as possible and stop before passing the one meter mark and hitting a wall. My problem is i don;t know how to make the cart go fast and then stop without cracking the end, I need suggestions!
  2. jcsd
  3. Dec 28, 2005 #2


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    Gold Member

    For starters, you might want to examine how compression forces affect an egg from different directions. It can be quite a strong object if approached properly.
  4. Dec 28, 2005 #3
    Keep it simple


    your best bet is to try and avoid any electronics unless you need them ( or have to use them for the project).

    A simple mechanical solution will be more relaible.

    You have two problems to solve
    1. Starting/Accelerating
    2. Stopping

    A mechanical motor that uses elastic bands would be easy for you to experiment with. A breaking system that simply locks the wheels up after a set distance (wire on a spool) would be a simple reliable system.

    Once you have a working model you can adapt it to give greater acceleration and smoother deceleration.

    Hope this helps

  5. Dec 28, 2005 #4
    I'ld hard boil the egg and coat it in some epoxy for starters. It's only cheating if you get caught.

    I think the string on spool idea of braking is brilliant, being wound up by the turning axle. What about compressed air for the forward propulsion??
  6. Dec 28, 2005 #5


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    Staff: Mentor

    When you say 'no padding' is that no padding inside (to protect the egg) or outside to buffer the cart?

    One could possibly use rubber bands to brace the egg - or does the egg have to be unrestrained in the cart? In that case, the only recourse it to decelerate the cart before it crashes.

    So the car has to travel one meter, then brake over one meter, and not hit the wall?

    Also, please do not double post. Thank you.
    Last edited: Dec 28, 2005
  7. Jan 3, 2006 #6
    This seems to be a mechanical solution only. You need to distribute the force evenly over the surface of the shell.
    I had to do this too. We were allowed to bring in our own egg but had to break it afterward to prove it was a real egg. I made a mold of the egg, cast a plaster duplicate with markings for alignment, then built the egg "cradle" specifically to the egg. It took some time but it was worth it, I got 110 on the grade because when the teacher broke the egg the yolk was broken but the shell was intact.
    If they let you use some padding it makes it a little easier, I had to use wood only. One other kid used saw dust:grumpy: got a passing grade because he techicaly followed directions
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