Hey guys, I'm not great at physics and my brain sometimes just doesn't get the sort of "implied" aspects of a problem. So I could use some help with an easy question. In projectile motion, there are certain constants given particular circumstances, right? I have to find the height of a table given the speed of a ball rolling off of it, and the distance away from the table that it lands. But I don't know how to fill in the holes. For example, I keep wondering about velocity in the Y direction. I don't know if its 9.8, or if that's the acceleration, and I just confuse myself with my lack of confidence about what's what, what's constant, zero, etc. having not given you guys any mathematical insight into this problem, could someone just relay to me what you would already know, given this particular circumstance?