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Homework Help: Projectile Motion Ball Problem

  1. Jan 29, 2006 #1
    A ball is thrown upward at an angle 30 degrees above the horizontal and lands on the top edge of a building 20 m away. The top edge is 5m above the throwing point. How fast was the ball thrown?

    ANS 20 m/s.

    I just can't seem to get this. It looks like there is a piece of info missing but I know that's not the case. Any hints?
  2. jcsd
  3. Jan 29, 2006 #2
    there are enough values to solve this problem
    you need to calculate horizontal component and vertical component
  4. Jan 29, 2006 #3
    have you tried using v2= u2+2as ? I think rearranging that for u should work.
  5. Jan 29, 2006 #4
    you've got to compute horizontal and vertical component because the ball was not thrown directly upward.. it was thrown at 30 degrees
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