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Homework Help: Y component of velocity

  1. Feb 5, 2009 #1
    1. The problem statement, all variables and given/known data
    An arrow is shot into the air at an angle of 59.4degrees above the horizontal with a speed of 20.9 m/s.

    (a) What are the x and y components of the velocity of the arrow 3 s after it leaves the bowstring?


    2. Relevant equations

    v(o)sin(theta)t+1/2(a)(t^2)

    3. The attempt at a solution
    I know the x is just trig and ends up being 10.6 but i dont understand how to find the y component. I thought you just used the above equation and plugged 3 in for t and -9.8 for a since its going down. I did that and I got the wrong answer. Any help would be much appreciated. Thanks a lot
    1. The problem statement, all variables and given/known data



    2. Relevant equations



    3. The attempt at a solution
     
  2. jcsd
  3. Feb 5, 2009 #2

    LowlyPion

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    Homework Helper

    Observe that the Vy (with positive up) is continually slowed by gravity.

    Vt = Vo - g*t

    or

    V3 = Vo*sinθ - g*3

    As you noted you have the x component already, so ...
     
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