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Homework Help: How long does a ball take to reappear at a certain point when it is thrown up?

  1. Sep 5, 2009 #1
    1. The problem statement, all variables and given/known data

    Sitting in a second-story apartment, a physicist notices a ball moving straight upward just outside her window. The ball is visible for 0.25 s as it moves a distance of 1.06 m from the bottom to the top of the window.

    How long does it take the ball to reappear?
    What is the greatest height of the ball above the top of the window?

    2. Relevant equations

    3. The attempt at a solution
    Last edited: Sep 5, 2009
  2. jcsd
  3. Sep 5, 2009 #2
    What kinematic acceleration equations would you considered appropriate when describing a ball falling down from a two story building? What forces are acting upon the ball as it falls down? What forces would you consider negliglble in this scenario?
  4. Sep 5, 2009 #3
    vf2 = vi2 + 2a[tex]\Delta[/tex]x

    x = xi + vit + 1/2 at2
  5. Sep 5, 2009 #4
    Move your coordinate plane so the x-axis is on the bottom of the window. You can ignore everything that happens below the window, in fact you can pretend that the ball was launched right at the bottom of the window. You know that it took .25s to travel 1.06m so now just find Vo
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