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Homework Help: Help Kinematics in 2d Question!

  1. Sep 16, 2005 #1
    Help!! Kinematics in 2d Question!

    Suppose the water at the top of Niagara Falls has a horizontal speed of 1.23 m/s just before it cascades over the edge of the falls. At what vertical distance below the edge does the velocity vector of the water point downward at a 49.4 degrees angle below the horizontal?
     
  2. jcsd
  3. Sep 16, 2005 #2
    The angle is given as 49.4degrees...
    And you know that tan of an angle will be y/x, and you're given the x velocity component, 1.23m/s...
    Now, you can form an equation...
    tan 49.4 = Vy/1.23
    Solve it for Vy... (Vy is that final vertical velocity)
    Then, to find the vertical displacement, use the formula (Vy)^2 = u^2 + 2gy given Vy, g and u. (It's a waterfall... so vertical velocity is assumably initially 0m/s)
    Solve it for y. :}
     
  4. Sep 16, 2005 #3
    Oh..

    Hey thanks for your help man ... BUT ... i got it wrong ..andi failed ..
     
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