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Homework Help: Find time of freefall based on little knowledge

  1. Nov 6, 2008 #1
    1. The problem statement, all variables and given/known data

    You fire a squirt gun horizontally from an open window in a multistory building and make note of where the spray hits the ground. Then you walk up to a window 5.0 m higher and fire the squirt gun again, discovering that the water goes 1.5 times as far. Ignore air resistance. How long does the second shot take to hit the ground?

    2. Relevant equations

    (delta)x = Vxt (delta)y = vyit + 1/2gt2

    3. The attempt at a solution

    I've put some time into this problem. I am having trouble including the 5m into the rest of the equation. I understand that I need to write a system of equations but so far they have been unsuccessful. I've also tried assigning values to see how far the water will go then work from there.

    I keep coming up with systems that equal zero. I am trying to include the 5 meters but that doesn't seem to help. Can someone point me in the right direction?
  2. jcsd
  3. Nov 6, 2008 #2


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    Science Advisor
    Homework Helper

    The only tings you need to know.
    Vertical acceleration is just 'g', horizontal acceleration is zero.
    And you can handle vert/horiz motion separately.

    The set of equations is then:
    v = u + a t
    s = ut+ 1.2 a t 2
    v2 = u2 + 2 a s

    Where u and v are initial and final velocity, s is distance, a is accelration
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