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Ball rolling down a segment then up a parabolic segment

  1. May 22, 2009 #1
    1. The problem statement, all variables and given/known data
    A 181 g ball is released from rest H=5.19 m above the bottom of the track shown in Figure. It rolls down a straight 21° segment, then back up a parabolic segment whose shape is given by y=x2/4, where x and y are in m. How high will the ball go on the right before reversing direction and rolling back down?

    2. Relevant equations

    3. The attempt at a solution
    I am not sure how to start this because everytime i go to one direction i hit a dead end.
    At the begining it has both Ki=0 and Ui=0 correct?
    Then at the final it has Kf and Uf right?
  2. jcsd
  3. May 22, 2009 #2
    Here is my work but I don't even think I am on the right track......

    This is for rolling down incline

    This is for rolling up the parabola
    EDIT: I put the wrong dominator in for the very last part when calculating Y it should be 4, but that anwser did not work either
  4. May 22, 2009 #3
    WOOOOOOW I am so sorry for wasting everyones times the parabola made me over think this equation since Ki+Ui=Kf+Kf.....energy would force the ball up the same height as it began.
  5. May 22, 2009 #4


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    Homework Helper

    The question gave you additional information to deceive you. Realizing this in the end only makes you understand energy conservation better. It's hardly wasting anyone's time.
  6. May 22, 2009 #5
    Yeah, I see what you mean but I didn't need to make a thread after.
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