[R. J. Ribando]

The modified spreadsheet as posted has a value in it for air of .00001536 kg/m^3, which is essentially a vacuum. The correct value given in my original spreadsheet is 1.19 kg/m^3 (approximately for sea level). Thus this modified spreadsheet does not contain any air drag - try adding wind to it and you'll see that there is no change in the trajectory. A strong wind in the negative direction should blow the projectile backwards! I don't know what a poof ball is, but I'd guess it probably has a lot of drag and that's why you had to fudge to match that experimental value.

If you really intend to ignore air drag, then get out your high school physics book and a piece of paper and pencil, because the solution for the projectile problem without air drag doesn't require the fancy numerical scheme implemented in this program!

rjr