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Homework Help: Bouncing Ball Problem - 2 Dimensional Challenge Lab

  1. Sep 25, 2011 #1
    1. The problem statement, all variables and given/known data
    The object of the lab is to find the diameter of the bouncing ball shown in the pdf attached. We are working with Logger Pro. The only 2 pieces of information that we have is that the ball is on the surface of the earth, where Ay=-9.81 m/s2, and that the frames are 0.05 seconds apart. This does not seem like anywhere enough information to go on, since that is all the information.

    2. Relevant equations
    I do not know where to begin this problem. I'm not sure how I could get to the end.

    3. The attempt at a solution
    I've tried to reason this out, but I do not see a way that, from this little info, we can achieve the diameter of the ball. Though I could track the ball on Logger Pro, and make a graph of its path, I do not see how this will do me any good.

    I do apologize for the lack of work, but I am truly stumped and lost on how to even begin on this problem. I suppose that's why my teacher called it a "challenge" lab.

    Attached Files:

    Last edited: Sep 25, 2011
  2. jcsd
  3. Sep 25, 2011 #2
    Hello jambobambo,

    This is an interesting problem. You stated the ball was on the surface of the earth. Does that mean that this simulation accounts for friction?

  4. Sep 25, 2011 #3
    He did not mention it, so I am assuming that, as usual, we are ignoring the friction. I think that he would have specified it if we were not.
  5. Sep 25, 2011 #4
    What you have to do is to find a distance scale for the pdf you've attached. If you know how long a unit length of your pdf is in the real world, you can measure the diameter of the ball in the pdf, and convert it to a real world length.
  6. Sep 25, 2011 #5
    This is true, but is there a way to find the scale factor from only the pdf? This is a quote from my instructor:
    "At first glance, it will seem as if insufficient information is given, as the scale of the video is not given and the surface on which the ball bounces cannot be seen. "
    I agree this is probably one of the keys, but finding a scale factor with only the pdf eludes me.
  7. Sep 25, 2011 #6
    Consider the fact that, neglecting air friction, any object in free fall falls under gravitational acceleration.
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