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Forces Can someone check this?

  1. Feb 5, 2006 #1
    Francesca dangles her watch from a thin piece of string while the jetliner she is in takes off from JFK Airport. She notices that the string makes an angle of 25° with respect to the vertical while the aircraft accelerates for takeoff, which takes about 18s. Estimate the takeoff speed of the aircraft.

    k so you know that the force of gravity is mg and it's going down, and that the acceleration is ma along the horizontal, and so can you take the tan(25)=a/9.8 to get an acceleration of 4.57m/s^2?

    And so for velocity you would get V=Vo+at

    thanks for reading
    Last edited: Feb 5, 2006
  2. jcsd
  3. Feb 6, 2006 #2


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    It seems to be correct. Which means the take-off speed is around 300 km/h which is realistic.
    Last edited: Feb 6, 2006
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