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Homework Help: Projectile motion(kinematics in 2d) question

  1. Sep 21, 2010 #1
    1. The problem statement, all variables and given/known data

    A skateboarder shoots off a ramp with a velocity of 5.1 m/s, directed at an angle of 58° above the horizontal. The end of the ramp is 1.4 m above the ground. Let the x axis be parallel to the ground, the +y direction be vertically upward, and take as the origin the point on the ground directly below the top of the ramp.
    (a) How high above the ground is the highest point that the skateboarder reaches?
    (b) When the skateboarder reaches the highest point, how far is this point horizontally from the end of the ramp?

    Before I even start doing the problem, I would have to know how the figure looks like so that I can draw it out on my paper, but I'm having troubles. I don't understand the part "take as the origin the point on the ground directly below the top of the ramp".
    Does it mean that the top(highest point) of the ramp is exactly at the origin? or does it mean that ground is 1.4m below the origin? Please help...
  2. jcsd
  3. Sep 21, 2010 #2


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    It means that the end of the ramp is vertically 1.4 m above the origin, so the skateboarder's initial vertical position y0 is 1.4 m.
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