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Homework Help: Determining arm length of catapult

  1. Feb 5, 2005 #1
    Hi, I have a big problem....
    I got a project on building a catapult. Easy, right? WRONG! We are supposed to determine the arm length without trial and error and I have no clue what to do. Please please help!

    Catapult is supposed to be built with 3/4" paper clamp as the only energy source and it must project a 2gram pingpong ball 1.5m. The catapult is a classic 2nd class lever. How would I calculate the arm length?
     
  2. jcsd
  3. Feb 5, 2005 #2
    It's all about torque.
     
  4. Feb 5, 2005 #3

    Andrew Mason

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    Don't you mean a 1st class lever? A catapult has the fulcrum in the middle.

    AM
     
  5. Feb 5, 2005 #4
    Sorry, I mis-typed it. It is a first class lever.
    How it is torque related? I tried to determine the centripetal acceleration, it didn't work out very well -_-'
     
    Last edited: Feb 5, 2005
  6. Feb 6, 2005 #5

    Andrew Mason

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    You don't need to worry about centripetal acceleration. You are concerned about the tangential speed of the arm, which is a function of the angular acceleration or torque.

    AM
     
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