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Homework Help: A simple question but i don't get it

  1. Jun 30, 2006 #1
    Hello, there's my question.

    A quarterback is running across the field, parallel to the line of scrimmage, at a constant speed of 2.5m/s, when he spots an open, stationary receiver straight downfield from him (ie, in a line parallel to the sidelines). If he can throw the football at a speed of 8.0m/s, relative to himself, at what angle, relative to the sidelines, must he throw it in order to hit the receiver? How far downfield was the receiver

    I drew a diagram but i got 72 degress and 25m as the answer... but the correct answer should be 18 degrees and 23m. where did i go wrong?

    i used tan = 8/2.5 and used that answer mutiplied by the velocity.

    Thanks

    Sorry i posted in the wrong place, just saw the head lines now...
     
    Last edited: Jun 30, 2006
  2. jcsd
  3. Jun 30, 2006 #2
    Show us your work.

    Hint: What is the velocity of the ball relative to the (static) ground.
     
  4. Jun 30, 2006 #3
    oh never mind i get it now = =

    it's suppose to be Tan angle = 2.5/8
    = 17.35 degrees

    then C^2 = A^2 + B^2
    = 22.80m
    thanks~
     
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