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Tough Concept Question

  1. Sep 22, 2008 #1
    Tough Concept Question!!!

    1. The problem statement, all variables and given/known data
    A rifle is used to shoot twice at a target using identical cartridges. The first time, it is aimed parallel to the ground and directly at the center of the bull's eye. The bullet strikes the target at a distance of HA below the center, however. The second time, the rifle is similarly aimed, but from 3.13 times the distance from the target. This time the bullet strikes the target at a distance of HB below the center. Find the ratio HB/HA.

    2. Relevant equations

    3. The attempt at a solution
    this is a very tough question i have come upon, i tried maybe going 2 x 3.13 as the Hb and dividing it by 2 but it doesnt seem to work, anyone have any ideas??
  2. jcsd
  3. Sep 23, 2008 #2
    Re: Tough Concept Question!!!

    HA = 1/2gt^2

    HB = 1/2gT^2

    s = ut
    3.13s = uT

    T/t = 3.13

    ... and so on
  4. Sep 23, 2008 #3
    Re: Tough Concept Question!!!

    could u perhaps clarify that?
  5. Sep 24, 2008 #4
    Re: Tough Concept Question!!!

    mal4mac is demonstrating that the time the bullet from rifle 2 is travelling through the air is 3.13 times the amount of time the bullet from rifle 1 travelled through the air.
    Now all you need to do is apply x = .5*g*t^2 to find the distance the bullet dropped iduring its flight.
    All you need is a ratio, so:
    x1 = .5*g*(t1^2)
    x2 = .5*g*(t2^2)


    x2/x1 = t2^2 / t1^2
    Since t2 is 3.13x greater than t1, plug this in and you have your ratio.
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