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Homework Help: Airplane velocity with wind

  1. Sep 25, 2012 #1

    joel amos

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    1. The problem statement, all variables and given/known data
    A plane is travelling at 350km/h northeast through a wind that is blowing 134km/h south.
    a) What is its true velocity and heading?
    b) What is its velocity directly east?

    I'm really not sure how to set this up. I need some nice pointers or someone to solve it and explain how the got the answer. Thanks :)
     
    joel amos, Sep 25, 2012
  2. jcsd
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  3. Sep 25, 2012 #2

    joel amos

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    Adding vector components

    1. The problem statement, all variables and given/known data
    A plane is travelling at 350km/h northeast through a wind that is blowing 134km/h south.
    a) What is its true velocity and heading?
    b) What is its velocity directly east?

    2. Relevant equations
    Fx = F*cosƟ
    Fy = F*sinƟ
    Rx = Ax + Bx + Cx etc
    Ry = Ay + By + Cy etc

    3. The attempt at a solution
    a) 272.27 km/h at 24.6 degrees north of east
    b) 247.49 km/h

    Am I correct? Can you please check my work? This is for a test!
     
    joel amos, Sep 25, 2012
  4. Sep 26, 2012 #3

    Simon Bridge

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    You will have some course notes about this sort of problem, with worked examples.
    Best practice is to start with those.

    If that is the way the question is really worded, then it is very badly worded indeed. What does "true velocity" mean in this context? Havn't you just been given the plane's velocity? If that is not "true" then what is it?

    Usually you are given the airspeed of the aircraft, and it's heading, and you have to work out the ground-speed and direction. Here it is not clear if 350kmph is the speed over the ground or what? The direction NE appears to be the direction of travel since part (a) asks for the heading (which direction the plane is pointing).

    I think this needs to be cleared up.
     
    Simon Bridge, Sep 26, 2012
  5. Sep 26, 2012 #4

    CWatters

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    I agree with Simon. Very missleading question.

    I would assume that the use of the word "travelling" and the fact that the question asks for the heading means that "350km/h northeast" is referring to the ground track (the path over the ground).
     
    CWatters, Sep 26, 2012
  6. Sep 26, 2012 #5

    Bandersnatch

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    Re: Adding vector components

    Looks correct. Good job.
     
    Bandersnatch, Sep 26, 2012
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