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Homework Help: Projectile motion

  1. Jun 14, 2010 #1
    1. The problem statement, all variables and given/known data
    A fireman 52.0 m away from a burning building directs a stream of water from a ground-level fire hose at an angle of 34.0° above the horizontal. If the speed of the stream as it leaves the hose is 40.0 m/s, at what height will the stream of water strike the building?


    2. Relevant equations
    Voy=Vo sin θ
    t= Voy / g
    y= Voy t - 1/2 g t2


    3. The attempt at a solution
    Voy= 40.0 m/s sin 34.0
    Voy= 22.37 m/s

    t= 22.37 m/s / 9.8 m/s2
    t= 2.28s

    y= 22.37 m/s (2.28s) - 1/2 (9.8 m/s2)(2.28s)2
    y= 25.53 m
    1. The problem statement, all variables and given/known data



    2. Relevant equations



    3. The attempt at a solution
     
  2. jcsd
  3. Jun 14, 2010 #2
    Your solution method is pretty much correct except for your calculation of the time. The equation you've used is [itex]t = v_{0y}/g[/itex], which is not valid. You can use [itex]t = x/v_x[/itex], however since the horizontal motion has no acceleration. That should do the trick.
     
  4. Jun 14, 2010 #3
    22.7 m thanks!
     
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