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Help with science project

Discussion in 'Ask The Pros' started by Prozach2, Nov 13, 2022.

  1. Prozach2

    Prozach2 Workshop Leader

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    My son is doing a science project on the fastest possible shape for a pinewood derby car. Things we'll be looking at include: aerodynamics, weight placement, weight, and the basic shape of the car. We'll be testing the cars using the official boy scout pinewood derby rules.

    When we've completed our research, I'd like to present our findings to an expert, and get their opinion. I don't believe it would take more than ten or fifteen minutes. Any of you pinewood derby champs interested in helping us out?
     
  2. Prozach2

    Prozach2 Workshop Leader

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    So, our lineup is complete. We’re starting with a basic block. Next, we have a shorter block which we’ll run with same weight and COG between axles to test impact of length. Assumption is, since height x weight = potential energy, longer car will go faster. Next, we’ll test weight. We’ve built a ladder car with no weights which we’ll run against the block. Theory is, less weight = less potential energy so block will win. Next, we have a block with numerous holes. We’ll use this to gradually add weight. Theory is, max weight of 5 oz will be fastest. So, at this point, hoping to have proved that 7” (max length) and 5 oz (max weight) is optimal. Next we’ll test COG WHICH I’m guessing will prove more towards back will win b/c equals more height in potential energy equation. Next, we’ll move on to aerodynamics. We’ll test, block, thinner block, tear drop, wedge, etc. with same length, width, and COG. Guessing thin will win and tear drop will prove to be inferior to wedge b/c can’t support optimal COG (no room behind axle for weights w/teardrop). Assuming theories are correct, we’ll test ladder cars moving COG further and further back. At this point, we’ll show how moving axles, bending axle, adjusting steer, etc. allows for moving COG back even more. Then we’ll run a few tests with and without fenders, polished axles, graphite, etc. showing benefits of eliminating friction. Then we’ll run one incorporating all we’ve learned. Attached is a picture of our lineup.
     

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