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Homework Help: 2 Dimensional Motion

  1. Sep 25, 2009 #1
    1. The problem statement, all variables and given/known data
    A quarterback claims that he can throw the football a horizontal distance of 196.6 m (215 yd). Furthermore, he claims that he can do this by launching the ball at the relatively low angle of 25° above the horizontal. To evaluate his claim, determine the speed with which this quarterback must throw the ball. Assume that the ball is launched and caught at the same vertical level and that air resistance can be ignored. For comparison, a baseball pitcher who can accurately throw a fastball at 45 m/s (100 mph) would be considered exceptional.

    2. Relevant equations
    delta x = V0x delta t

    3. The attempt at a solution
    70.93 m/s

    Tried finding the maximum height the ball would reach by using 1/2 of the length (98.3) and then plug it into the max height equation : delta y = ((initial velocity)^2 sin (theta)^2)) / 2 acceleration of gravity (-9.8 m/s^2)

    This would have given me the answer for the velocity needed sine the initial and final velocity would be the same in the x-direction.
    Last edited: Sep 25, 2009
  2. jcsd
  3. Sep 25, 2009 #2


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    Science Advisor
    Homework Helper

    Welcome to PF!

    Hi IAmSparticus! Welcome to PF! :wink:

    Show us your full calculations, and then we can see what went wrong, and we'll know how to help.

    Use the usual constant acceleration equations. :smile:
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