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Homework Help: Am I taking the right approach? (Finding final velocity)

  1. Oct 23, 2011 #1
    I've been given this problem http://i.imgur.com/7XtYt.png and I had no idea of how to come up with an answer since it is a circular path. The only thing that occurred to me is find the initial height using the chord length formula for a circle and then treat that chord as the hypotenuse of a right triangle. After finding "the height" that way I can then use an energy conservation approach to get the velocity and I get 16.78 m/s.

    Is that a correct way of doing it?. Even if it is correct, not many people would remember the chord length formula so I doubt our professor intended for it to be solved that way. There has to be an easier way to do it.
     
  2. jcsd
  3. Oct 23, 2011 #2

    Delphi51

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    I find "chord length" confusing.
    To find the height, I drew a horizontal line from A to the vertical line.
    The distance from the center of the circle to the line is 30*cos(40) = 23.
    So the height at A is 30 - 23 = 7.
    I get the same final answer answer you did.
     
  4. Oct 23, 2011 #3
    Wow, this is more straight forward. I don't see how I see it myself.

    This is what I mean by chord length . http://i.imgur.com/aNTUA.png

    Thanks :)
     
  5. Oct 24, 2011 #4

    Delphi51

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    Fascinating! I must attempt to derive that formula.
    Funny, I never ran across it before.
     
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