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Kicking a Field Goal

  1. Sep 1, 2008 #1
    1. The problem statement, all variables and given/known data
    If the ball is kicked at 53 degrees above horizontal what must the initial speed be if it is just to clear the crossbar. I know the ball is distance in the x direction is 10.98 m and the height of the goal post is 3.05 m.

    2. Relevant equations
    I think I should be using the equations Voy=Vosin(theta) and Vox=Vocos(theta)

    3. The attempt at a solution
    No idea how to solve without having any veclocities to plug into the above equations.
  2. jcsd
  3. Sep 1, 2008 #2


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    Staff: Mentor

    Welcome to the PF. I moved your thread from Advanced Physics to Introductory Physics.

    You have listed two of the equations that you will need to solve the problem. Now list the equation for motion x(t) in the horizontal direction, in terms of Vx(t) and Vox and t. And list the equation for motion in the vertical direction y(t), in terms of Vy(t) and Voy and t and the acceleration of gravity g.

    With those equations of motion, and the ending (x,y) point you are given, do you see how you may not need to know the initial velocity Vo?
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