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Homework Help: Plane flight

  1. Sep 29, 2008 #1
    A light plane attains an airspeed of 470 km/h. The pilot sets out for a destination 800 km due north but discovers that the plane must be headed 17.0° east of due north to fly there directly. The plane arrives in 2.00 h. What were the (a) magnitude (in km/h) and (b) direction of the wind velocity? Give the direction as an angle relative to due west, where north of west is a positive angle, and south of west is a negative angle.

    Pyj-800j=wj
    Pxi=Wxi

    attempt

    tan inverse
    (wx/WY)

    then i got lost and do not know how to start the problem
     
  2. jcsd
  3. Sep 29, 2008 #2

    Andrew Mason

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    Draw a vector diagram. One vector [itex]\vec v_{pa}[/itex] represents the velocity of the plane relative to the air. The other vector [itex]\vec v_{ag}[/itex] represents the velocity of the air relative to the ground. What does the resultant vector ([itex]\vec v_{pa}+\vec v_{ag} = \vec v_{pg}[/itex] represent? (Hint: I have given you a hint). Do we know the length of this vector? Do we know the length of [itex]\vec v_{pa}[/itex]? Do we know its angle relative to [itex]\vec v_{pg}[/itex]? Resolve the North and West components of [itex]\vec v_{pa}[/itex]. What do these components plus the North and West components of [itex]\vec v_{ag}[/itex] have to add up to?

    AM
     
    Last edited: Sep 29, 2008
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