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Homework Help: Finding X and Y Components of a Vector

  1. Feb 3, 2010 #1
    Find the x and y components for the given vectors below.

    Magnitude: 318, Angle: 260 degrees

    Magnitude: 140, Angle 180 degrees

    No units were specified.

    I tried using trigonometric equations to figure them out, but it isn't working so far. What am I doing wrong? For instance, I used cos(260)*318 to get the x component, but Webassign said I was incorrect. Please help me!
  2. jcsd
  3. Feb 3, 2010 #2


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    Staff: Mentor

    Which quadrant is the angle 260 degrees in? Why does that matter?
  4. Feb 3, 2010 #3
    Yes, I'm sure it does matter, but this is why I'm confused. We've never dealt with angles larger than ninety degrees in class and yet, we are expected to know how to do this. I started by subtracting the 260 from 360 and I got 100 degrees. So, I used that angle and divided the resulting triangle in half so I could have two right triangles.

    Each triangle had a ninety degree angle, a fifty degree angle (100/2), and a forty degree angle (180-90-50). Since the hypotenuse/magnitude was 318, I divided that by two to get the x components of both triangles... And that's where I got confused. I'm completely lost. Sorry I can't explain myself very well. There wasn't much instruction other than what I gave beforehand.
  5. Feb 3, 2010 #4
    Here's a simpler way to go about it. We know the angle is 260 right? It would fall into the third quadrant. 90 degrees in each quadrant. There is 180 in the first 2, and 260 -180 = the angle into the third quadrant.
  6. Feb 3, 2010 #5
    Ohhhh! Okay! That helps a lot; I've never heard this sort of problem explained like that, but it made it much easier to see the problem visually. Thanks bunches!
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