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Homework Help: 2D motion question

  1. Aug 31, 2006 #1
    I'm having a bit of trouble with this problem, I thought I knew how to solve it but can't get what is listed as the correct answer in the key.

    An airplane starting from airport A flies 300 km east, then 410 km at 25.5° west of north, and then 150 km north to arrive finally at airport B.
    The next day, a pilot flies directly from A to B in a straight line, what is the distance of this flight?

    I was able to find the correct angle, 77.89 degrees north of east, and I tried to use the Pythagorean theorem with the X and Y components to find the length of the resultant, but the website (it's a webassign.net problem for a class) keeps telling me I have the wrong answer. Any insights on what I'm doing wrong? The two answers I keep coming up with are 371.17 km and 333.94 km.

    thanks for your time!
     
  2. jcsd
  3. Aug 31, 2006 #2

    lightgrav

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    You have the wrong E and N components ...
    the N component by itself is over 500 km (150 + almost 400).
    Show your work!
     
  4. Sep 1, 2006 #3
    You can do this graphically. Make a drawing to scale, use a protractor also. Then you can tell where your errors lie.
     
  5. Sep 1, 2006 #4
    Thanks for your advice, I reworked it and found the correct components. I had gotten a little thrown by the "west of north" angle and made a mess of some negative signs when doing the trig.
    Thanks again!
     
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