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Homework Help: Calculating velocities with only acceleration and time

  1. Sep 10, 2009 #1
    This was a basic physics experiment. A ball was thrown upward and then caught. Calculate initial and final velocity given: acceleration= -9.8m/s^2 (gravity); time= 2.12sec

    delta x=Vi*t+(.5)(t)^2

    I actually don't know where to begin. I don't know an equation for velocity that doesn't require displacement (which I also need to find).
  2. jcsd
  3. Sep 10, 2009 #2


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    Gold Member

    if it's caught at the same horizontal level, then vi=vf [note the direction of each, one is + and the other is -]


    ps. welcome to PF :)
  4. Sep 10, 2009 #3
    Thanks for the help. So how would I figure out which equation to use?
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