physicsnewton's laws
posted by mani .
an aeroplane is flying in a horizontal circle with airspeed of 480 km/h. The wings of the plane are tilted at 40 degrees to the horizontal. What is the radius of the circle and how long does it take the plane to complete one full circle?

change km/hr to m/s
Look at a vector diagram. mg is down, lift is perpendicular to the tilt angle.
You need to realize the vertical part of lift is equal to mg (so mg=Lift*sin40
That give you lift. Now, the portion of Lift keeping the plane accelerating inward is lift*cos40.
So set lift*cos40=mv^2/r, and mass divides out, so you can calulate r.
period is the final easy part:
time=2PIr/velocity 
thank you so much :)