CompuServe Messages

Assuming constant gravitational force and no air resistance, you're talking about a parabola whose axis passes through the point of maximum height. Assuming target at the same height as the firing point, that occurs exactly half way between the two points, or at exactly half the interval of the shell's travel time. On these assumptions, given distance d between gun and target and maximum height achieved as h, we can write; y = h – b * (x – d/2)^2 where y is the height at any point, x the distance from the firing point. The value of b is easily obtained, since we know that when x=0, y must equal zero, too. Thus; b = 4 * h / (d^2) Depending on what calculations you have in hand already, the above should fit nicely into your work. Of course, if you had a spinning projectile moving through atmosphere with a cross wind and perhaps light precipitation, you'd need to do other things. [Like duck, perhaps? 🙂 ] –Jim