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Homework Help: Speed of a plane given distance and time equation.

  1. Mar 21, 2009 #1
    an aircraft at an altitude of 10 000 m is flying at a constant speed on a line that will take it directly over an observer on the ground. if the observer notes that the angle of elevation o the aircraft is 60 degrees and is increasing at a rate of 1 degree per second find the speed of the plane in metres per second.

    i got the formula for the equation as 10 000/(Tan (a+x))=m
    a=angle x=seconds m=metres across.

    i cant think why it would be incorrect. the velocity is metres per second so delta M over Delta T or Delta y over Delta x (the gradient function)
    that didnt get me anywhere because i didnt know wat to sub in for the equation

    then i simply took an m value and a x value and used the average velocity formula but as expected it changed.

    plllllllllleeeassse i know the answer is staring me right in the face, im just temporaily blind. help me.
  2. jcsd
  3. Mar 22, 2009 #2


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    Hi brandy! :smile:

    (have a delta: ∆ :wink:)
    hmm … your notation is horrible, and you've left out half of the rhs :frown:

    you should have ∆x = v ∆t = 10 000/(Tan (60º + ∆t)) - 10 000/(Tan (60º)) :smile:
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