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Homework Help: PE and KE of a water balloon

  1. Apr 11, 2008 #1
    A prankster drops a water balloon from the top of a building on an unsuspecting person on the sidewalk below. If the balloon is traveling at 30.3m/s when it strikes a person's head ( 1.5m above ground). How tall is the building? Neglect air resistance.

    PE= KE
    mgh=.5*mv^2
    h= v^2/2g
    h=(30.3m/s)^2/(2*9.81m/s/s)
    h=918.09 m^2/s^2 / 19.62 m/s/s
    h= 46.8m

    total height = 1.5m + 46.8m = 48.3m
    is this right? Is the sig figs right?

    Thank you
     
  2. jcsd
  3. Apr 11, 2008 #2
    Looks right.
     
  4. Apr 12, 2008 #3
    easy.
     
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