Slide 4 of 12
Notes:
Here we see the real reason a frizbee seems to float on air. First, it’s rotation stabilizes it in an orientation where the rotation axis is vertical; when it’s moving forward in that orientation, the air flowing over the curved top has to move faster (relative to the frizbee surface) than that passing beneath because it has to travel a greater distance in the same time. Bernoulli’s equation says that pressure is least where speed is greatest, and so the reduced pressure at the top of the frizbee provides the lift that keeps the frizbee in the air until it stops moving forward.
This, of course, is the same reason the airplane’s wings are able to lift the airplane so long as the engines are moving it through the air.
