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Unit Vector Velocity

  1. Sep 15, 2009 #1
    1. The problem statement, all variables and given/known data
    Exactly 2.9 seconds after a projectile is fired it has the velocity (9.0i +4.5j) m/s.
    What is the horizontal range of the projectile.

    2. Relevant equations

    3. The attempt at a solution
    Range = [((9.0i^2 + 4.5j^2)^1/2)^2 x sin2(arctan(4.5/9))]/ 9.8 m/s/s
    Range = 8.3 m but this is incorrect.
  2. jcsd
  3. Sep 15, 2009 #2

    D H

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    Staff Emeritus
    Science Advisor

    Of course that's not correct. Look at the units, for one thing. For another, you aren't accounting for that 2.9 seconds.
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