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Component vectors

  1. Nov 26, 2009 #1
    Hello, im slightly confused with component vectors.

    if im trying to add two vectors, which are 33m/s [W33E] and 53m/s [N54W] i have to
    break them down in to x and y component.
    i can get them by using cos and sin.

    but there are some occasions where im not sure if the degree im using is correct.

    for example for 33m/s the xcomponent would be 33cos33 and ycompoent would be 33sin33.

    when do we ever use 33cos-33 ? beacuse i know there are some occasions where negative angle is neccesary or even (180-33) obtuse angle to find the component.

    please could anyone clarify this for me thanks,
  2. jcsd
  3. Nov 26, 2009 #2
    I don't understand your notation [W33E]... are they something to do with the compass points?
  4. Nov 26, 2009 #3
    To add two or more vectors, just add their x and y components respectively. Simple as that. Your notation seems odd, though.
  5. Nov 26, 2009 #4


    Staff: Mentor

    Your [W33E] notation is incorrect. The other heading, [N54W], means 54 degrees west of north. The first one should probably be either N33E or S33E.
  6. Nov 26, 2009 #5


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    Draw the vector with its tail at the origin. Then draw a polar coordinate angle from the positive x axis to the vector. It doesn't matter whether you go counterclockwise with a positive [itex]\theta[/itex] or clockwise with a negative [itex]\theta[/itex]. Do whichever seems more natural for the vector you are considering. In either case you will get [itex]x = r\cos\theta,\ y = r\sin\theta[/itex].
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