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Homework Help: Airplane flying in a circle

  1. Oct 21, 2004 #1
    I tried workin this problem out.. and it's not working!! :frown:

    ---
    An airplane is flying in a horizontal circle at a
    speed of 48.1 m/s. The 94.1 kg pilot does not
    want his radial acceleration to exceed 7:.39 g.
    The acceleration of gravity is 9.8 m/s^2

    1) What is the minimum radius of the circular
    path? Answer in units of m.

    7.39g (9.8m/s^2) = 72.422 m/s^2
    do I need to square root 72.422??



    2) At this radius, what is the net centripetal force
    exerted on the pilot by the seat belts,
    the friction between him and the seat, and so
    forth? Answer in units of N.

    N = mg + m (V^2/m)

    is this the right formula?? what would m and v be??
     
  2. jcsd
  3. Oct 23, 2004 #2
    Is this right??

    Speed = 48.1 m/s
    g = 9.8 m/s^2

    Problem #1

    7.39 g (9.8 m/s^2) = A
    A = 72.422

    R = V^2 / A
    R = (48.1 m/s)^2 / 72.422
    R = 31.94

    Problem #2

    F = mV^2 / R
    What's m??
    F = (?)m x (4.8)^2 / 31.94
     
  4. Oct 23, 2004 #3
    Remember that A(centripital) = v^2 / R....

    ...so your answer to problem 1 looks correct.

    On problem 2, how did you go from a velocity of 48.1 m/s to that of 4.8 m/s? The mass would just be the pilots mass...because its asking for the centripital force acting on the pilot.
     
  5. Oct 23, 2004 #4

    Sorry I meant 48.1 m/s not 4.8 m/s...

    So it would be:

    Fc = m (V^2/R)
    Fc = 94.1 [(48.1)^2 m/s / 31.9)

    Fc = 6824.78 N?
     
  6. Oct 23, 2004 #5
    Looks good. :-D
     
  7. Oct 23, 2004 #6

    Thank you!! :biggrin:
     
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