I've been working on making a package of Java classes to use in developing programs/games using actual physics instead of 'best guess'. The problem is I'm pretty rusty with the whole subject, and am lost trying to get a formula for projectile trajectory with air resistance taken into account. I found this, https://www.physicsforums.com/showthread.php?t=27331&page=1&pp=15&highlight=projectile+trajectory, set of formulas which seem to have helped the person who asked the same question as me, but the thing is, it's completly lost on me. If anyone could explain the formulas mean and how they work I'd be very appreciative. Also, if anyone knows of any other resources or projects similar to what I'm working on, I'd very much like a point in that direction. Thanks!