Physics for Stupid People like me

You talk about the bouncing ball right? Going higher and higher for no obvious reason. Normal flawy code is like this:

position=position+velocity
velocity=velocity+acceleration
If [ball hit floor] Then velocity=-velocity

The ball will gain more and more height, because when the ball hit the floor, first acceleration due to gravity is added, then velocity is inverted, resulting in the ball launching upwards with greater speed than it came down with, the fix however is simple:

position=position+velocity
velocity=velocity+½acceleration
If [ball hit floor] Then velocity=-velocity
velocity=velocity+½acceleration

This can be made a bit smoother:

position=position+velocity+½acceleration
velocity=velocity+acceleration
If [ball hit floor] Then velocity=-velocity