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Homework Help: Determine the plane's ground velocity.

  1. May 12, 2008 #1


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    1. The problem statement, all variables and given/known data

    1 A light plane is travelling at 175km/h on a heading of 8° east of north in a 40-km/h wind from 80° east of north. Determine the plane's ground velocity.

    2. Relevant equations

    cosine law

    3. The attempt at a solution
    I found the resultant to be 191 km/h but the answer is 167 km/h
    Last edited: May 12, 2008
  2. jcsd
  3. May 12, 2008 #2
    Show us your working a.a it will help us see where you have gone wrong if you have. :smile:
  4. May 12, 2008 #3


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    Homework Helper

    Hi a.a! :smile:

    You've added the 2*40*175*cos72 instead of subtracting it.

    I expect you've drawn the triangle wrong.

    If the velocity of the plane the air and the ground are P A and G, then the question asks for P - G, which is (P - A) + (A - G).

    Draw the triangle so that the arrows go the right way. :smile:
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