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Homework Help: The acceleration of a descending airplane

  1. Sep 17, 2012 #1
    1. The problem statement, all variables and given/known data

    An airplane descends in a circular pattern with a constant radius of 250 meters. The airplane has a horizontal speed of 75 m/s (constant) and a downward
    speed of 5 m/s, which is increasing at a rate of 2 m/s2

    Determine the acceleration of the airplane.

    2. Relevant equations

    an = v2 / ρ

    a = √(at2 + an2)

    3. The attempt at a solution

    Finding the acceleration for a circular motion is easy, but I am having trouble including the downward acceleration. Any help is greatly appreciated!

    Attached Files:

  2. jcsd
  3. Sep 17, 2012 #2


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    Science Advisor

    If all else fails, derive it from first principles.

    Assuming that the aircraft is at height h and is circling the origin, can you write down its position as a function of time? If so, what's its acceleration?
  4. Sep 17, 2012 #3
    What equation could I use to include the height and downward speed as a function of time?
  5. Sep 17, 2012 #4


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    Homework Helper

    You figured out the centripetal accleration, and the problem states the downwards acceleration is 2 m / s2, which would be the components of the acceleration vector (horizontal and vertical). To get the magnitude, take the square root of the sum of the squares of the components.
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