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Homework Help: Really need help getting started precal honors problem

  1. Feb 26, 2006 #1
    an airplane's velocity with respect to the air is 400 kilometers per hour, with a bearing of 45degrees. The wind at the altitude of the plane has a velocity of 40 kilometers per hour with a bearing of N50degeeesE. What is its speed relative to the ground

    Ok im not asking you to do the problem for me i just dont have all my notes on me and the book isnt much help i would really appriciate it if someone could help me get started on this problem, thanks.
  2. jcsd
  3. Feb 26, 2006 #2
    Did you try drawing it out? That should give you an idea.
  4. Feb 26, 2006 #3
    Also, Parallelogram Law of Vector Addition.
  5. Feb 26, 2006 #4
    Break both things into vectors and then add them up....
  6. Feb 26, 2006 #5
    Also, you can't say bearing of N50E, because a bearing is presumed to start from the north and go clockwise. So you only say a bearing of so and so degrees.
  7. Feb 27, 2006 #6


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    Actually, it is common in navigation to give a bearing like that. Of course, "N 30 degrees E" is just an angle measured 30 degrees east of north- since that is clockwise, assuming that the x-axis is east, that corresponds to an angle in the coordinate system of 60 degrees.

    Of course, as long as you are consistent and write your answer correctly, there is nothing wrong with measuring angles clockwise from north.

    In any case, draw a picture, be careful of your lengths and angles and look for triangles.
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