Excellent!
Well Done! Exactly the kind of tutorial needed in and worthy of the flash tutorial collection. Would love to see more like this. This flash covers a very good ball bouncing behavior, collision detection, interacting with the ground, and more. The math is fairly advanced and complicated but it is explained thoroughly and can be understood with a little effort from those challenged by math; it's deals with trigonometric functions and differential equations and it explains and makes allowances for some of flash's limitations in dealing with math expressions. Very Good and I would love to see more like this!