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Rotational kinematics

  1. Oct 27, 2005 #1
    A quarterback throws a pass that is a perfect spiral. In other words, the football does not wobble, but spins smoothly about an axis passing through each end of the ball. Suppose the ball spins at 7.04 rev/s. In addition, the ball is thrown with a linear speed of 21.6 m/s at an angle of 47.0° with respect to the ground. If the ball is caught at the same height at which it left the quarterback's hand, how many revolutions has the ball made while in the air?

    I translated 47.0 degrees into radians and 7.04 into radians per sec and then used the rotational kinematics equation angle theta = 1/2 (omega initial - omega) * t, and then i multiplied t by 7.04 rev/sec... what am i doing wrong?? help! thanks
  2. jcsd
  3. Oct 27, 2005 #2

    Doc Al

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    Staff: Mentor

    Start by figuring out how long the football is in the air.
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