A=v^2/r solve for v, solve for r

To rearrange these for v and r we must use BEDMAS.

First, times both sides by r, getting Ar = v²r/r
You can cancel out r/r to get Ar = v²

To get v, square root both sides. √Ar = √v²
Cancel out the square root and the squared v = √Ar

To get r, go back to Ar = v², then divide both sides by A. rA/A = v²/A
Then cancel out A/A to get r. r = v²/A

If there was no gravity then their would be no downword force on the football to have it return the the grownd, and if there was no friction (mainly air friction) then there would be no opposing force the stop the ball from moving through the air allowing the ball to travle ∞.