1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Airplane turning

  1. Sep 30, 2007 #1
    1. The problem statement, all variables and given/known data
    A supersonic airplane is flying horizontally at a speed of 2840 km/h. What is the centripetal acceleration of the airplane, if it turns from North to East on a circular path with a radius of 86.5 km?
    How much time does the turn take?
    How much distance does the airplane cover during the turn?

    2. Relevant equations
    a = v^2/r

    3. The attempt at a solution
    I got the acceleration which = 7.9 m/s but for calculating the time can I use Wf = Wo + at and use 90 degree for the initial and 0 for the final to solve for t
  2. jcsd
  3. Sep 30, 2007 #2
    No I think you need to use:
    [tex]v=\frac{2R \pi}{T}[/tex]

    where T is the time to make 1 rotation, in your problem the plane doesn't make a full rotation so the T you need will be a fraction of the original T depending on how much of a rotation the plane makes
  4. Sep 30, 2007 #3
    I am getting a really large number, 688.94 s, that doesn't seem logical?
    I did...
    (2 * 86500m * pi)/788.89 m/s
  5. Sep 30, 2007 #4
    well that's to make 1 full rotation but the plane doesn't make a full rotation.
    from N to E is how many degree's? or what fraction of the entire x-y plane?
    take that fraction and multiply that time by it and you'll get the time to make just that part of the rotation.
  6. Sep 30, 2007 #5
    Oh okay so thats for a full revolution ok I got it then, just multiply by 1/4. Thank you.
  7. Sep 30, 2007 #6
    okay so for the third part of the question to find the distance can we use...
    W = (2pi/T) * (1/4)
    W = Change in theta/Change in time
  8. Sep 30, 2007 #7
    Hm..well if the plane travel's 1/4 of the circular path that should be 1/4 of the diameter of the circle?

    I've never seen those equations you're using but I've just learned circular motion from the book so far until Tuesday.
  9. Sep 30, 2007 #8
    I just tried 1/4 of the diameter but it says incorrect :( I don't know what to use.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook