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Homework Help: Constant acceleration

  1. Jun 19, 2012 #1
    A Cessna aircraft has a liftoff speed of 120 km/h.

    (a) What minimum constant acceleration does the aircraft require if it is to be airborne after a takeoff run of 250 m?
    (b) How long does it take the aircraft to become airborne?

    I tried using an equation for constant acceleration and plugged in: .277^2=0+2a(250). When I solved for a I got .000153 and it was incorrect. any suggestions?
     
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  3. Jun 19, 2012 #2

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    Where did the "0.277" figure come from?

    (Edit: And does 27.7 centimeters per second even sound like a reasonable velocity for the liftoff speed of a Cessna aircraft?)
     
  4. Jun 19, 2012 #3
    After I converted the kilometers per hour to meters per second
     
  5. Jun 19, 2012 #4

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    You might want to try that calculation again. :smile:
     
  6. Jun 19, 2012 #5
    thats my problem it should be 44.44m/s
     
  7. Jun 19, 2012 #6
    thanks
     
  8. Jun 19, 2012 #7

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    Ummm, :uhh: Try that one more time. :smile:
     
  9. Jun 19, 2012 #8
    i meant 33.33m/s haha
     
  10. Jun 19, 2012 #9

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    That sounds better. :approve:
     
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