Demo and physical engine for pda TOUCH

I wish to create a physical engine for pda touch (with touchscreen). This engine will be able to make it possible to manage gravity, the collisions against walls traced by the user thanks to the touchscreen (lines, curves…), and the speed of an object. A demonstration must be also to create in order to be able to launch a ball with the finger and the ball must rebound/slip/roll on the curves plotted with the finger by the user. The demonstration must function with mobile Windows 6.0 and on pda HTC Touch.