physics
posted by Brittany .
The airplane can take off when its airspeed (speed of the air flowing over the wing) is equal to 65 knots. What is the length of runway required for the plane to take off if there is a 21 knots head wind? The runway at the Tallahassee Regional Airport has a length of 8000 ft.

change (6521)knots to m/s. You can do that by putting this in the google search window:
(6521)knots in m/s
Then
speedabove^2=2ad where d is the length of the runway (in meters), and I assume you messed up the problem, you are looking for acceleration a.
and, once you can find a, you can figure the thrust of the engines:
Thrust= mass*a 
so how would i go about finding acceleration?

a= .5*speed^2/distance
make certain your units are in meters, and seconds. 
thank u so much!! ^w^