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Homework Help: I and j components

  1. Sep 19, 2006 #1
    My professor explained this problem but he said that it was so simple so he stopped and we all feel dumb. Please help if anyone knows how. Thanks.

    A light plane attains an airspeed of 330 km/h. The pilot sets out for a destination 800 km to the north but discovers that the plane must be headed 20° east of north to fly there directly. The plane arrives in 2.266 h.
    What was the i-component of the wind velocity vector (in km/h)?

    What was the j-component of the wind velocity vector?
  2. jcsd
  3. Sep 19, 2006 #2


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    distance = speed * time (assuming constant speed)

    So the plane travels some distance with its airspeed (speed relative to air). But it is flying in the air 20° east from north to that distance.

    What must the air be doing in the same period of time to get the plane to 800 km N?

    One needs to define which direction is i and which is j (normal to i). Perhaps pick i to be due N, and j to be due east.
    Last edited: Sep 19, 2006
  4. Sep 19, 2006 #3
    My inturpretation of the question is that he has to fly 20 degrees east of north to correct for wind.

    If the plane is travelling at 330 km/h for 2.266 h then the distance travled = 330*2.266 = 747.78km

    but the initial distance before the wind was 800, and we know there is an angle of 20 degrees so hence you can draw a vector triangle, and the unknown side will equal the i component. hope this helps, and doent breach this forums rules for helping with questions.
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