1.6 = 3.1*tan(35*pi/180) - 0.5*9.81*3.1^2/(v^2 cos^2(35*pi/180))

Uh oh! Wolfram|Alpha doesn't run without JavaScript.

Please enable JavaScript. If you don't know how, you can find instructionshere.Once you've done that, refresh this page to start using Wolfram|Alpha.