Create some more tutorials on the Physics section of your site
As of now, there is only a tutorial on collision detection, which is VERY useful. But there are some other things that you could add, such as making a sprite look like it is jumping, or a ball that could bounce around until it eventually came to a stop.
Ajr Khan commented
Ahmet Mete ÇOM commented
This is also a very good idea, because it will have to include lots of maths, which is usefull in many more ways than just physics.
As far as the sprite that /looks/ like it's jumping goes, I think that a simple texture atlas and decrease of the y coordinates (unless the sprite is jumping down) would work. Creating some type of game gravity is a great idea, though (the ball example)!