1. Not finding help here? Sign up for a free 30min 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!

A pilot goes into a loop

  1. Nov 18, 2004 #1
    A pilot goes into a loop....

    A 75 kg pilot goes into a loop. At the top of the loop, where the plane is completely upside down for an instant, the pilot hangs freely in the seat and does not push against the seat belt. The airspeed indicator reads 120m/s. What is the radius of the planes loop?


    I did Ac=v^2/r

    substitute 9.8 for ac and 120 for v, so....

    9.8=120^2/r

    and when you do that, the radius is 1469.39 m.


    My friend disagrees and says the loop should only be 19.36 meters. He used F=ma, then put that into the equation, to get 19.36.


    Can someone say who did it right?
     
  2. jcsd
  3. Nov 19, 2004 #2

    Galileo

    User Avatar
    Science Advisor
    Homework Helper

    First of all. Which answer is more plausible. Surely I don't see an airplane make a loop with a radius of 19.36 meters.

    But more rigorously. The gravitational force on the pilot equals the centrifugal force, since he doesn't push against the seat. So you're right.
     
  4. Nov 19, 2004 #3
    Thank you, and yes, I had thought of the airplane making a 19m loop. Not gonna happen.
     
  5. Nov 19, 2004 #4
    You could still use F = ma, I don't know why you would, but you'd just you'd have to use it properly.

    [tex]F = ma[/tex]
    [tex]F = \frac{mv^2}{R}[/tex]
    [tex]mg = \frac{mv^2}{R}[/tex]
    [tex]g = \frac{v^2}{R}[/tex]
    [tex]9.8 = \frac{120^2}{R}[/tex]
    ...
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: A pilot goes into a loop
  1. Stunt pilot (Replies: 3)

  2. Force on the pilot (Replies: 3)

Loading...