Wow!!!!! That was really interesting. I especially liked the equations for 2 dimensional projectile motion given in the beginning of the article. Still, one thing which I felt was rather incorrect was the fact that you assumed there was no friction while the whole concept of tanks moving is based on friction. Also, when we use hulls like hornet ,they sometimes start skidding (you probably know what i mean ) which wouldnt be possible if there was no friction. As for tanks not slowing down while going uphill,you make a very valid point. something i find interesting is that for some very steep slopes,tanki physics somewhat resembles our physics(you slow down while going up).