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Center of mass for derby car

  1. Jan 21, 2008 #1
    I am trying to determine the center of mass of a pinewood derby car. Any suggestions on how this can be done?
  2. jcsd
  3. Jan 22, 2008 #2


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    On paper, my measuring the shape and mass of each component - calculating their individual CofG then calculating the overall value.
    Or just balance the finished car on a knife edge.
  4. Jan 22, 2008 #3
    Thanks. There is also a lot of discussion as to where the weight in the car shoud be placed. I assume the weight should be placed as low as possible and as far back on the vehicle as possible. Your input is appreciated.
  5. Jan 22, 2008 #4


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    Hang the car from the middle of a string, the hanging (free) end of the string will pass through the cm. Do this from 2 different points, the intersection is your cm.
  6. Jan 22, 2008 #5

    Andy Resnick

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    To find the center of mass, you actually need *3* different 'hangings' because the car is 3-dimensional. Two will identify the line that passes through the center of mass, the third will reduce it to a point.

    In any case, IIRC, the number 1 design consideration is the wheel friction. The wheels must spin freely and be lubricated. Then, the weight and aerodynamics come into play.
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