From an engineering standpoint, traditional exterior ballistics analyses are like the proverbial "red-headed step-child" when compared to aerodynamical analyses. Basically, a long time ago, a "standard" projectile was defined, and all analyses use that as a standard by which ballistic comparisons are made. Thus, the coefficient of drag, a common aerodynamic term, does not show up in traditional formulae. Instead, the Ballistic Coefficient (or BC) is used.
Traditional ballistics can take a bit of time and research to get a handle on. Therefore I would suggest the following course of action:
1. If you are a high-school student, just go with the point-mass, no-drag approach posted by Erasmus earlier. It is a good starting point for understanding the concepts.
2. If you are a college student, you could go with the point-mass, no-drag approach if you're in a basic math class, or if you are in an advanced class, I'd suggest studying traditional ballistics and presenting that.
Here is a good web site on traditional exterior ballistics that's been around for several years:
[url]http://internet.cybermesa.com/~jbm/ballistics/ballistics.html[/url]
Also, the best text I've found is a recent, hard to find book written by the late R. L. McCoy, a former scientist at the U.S. Army's Ballistics Research Laboratory. It's titled "Modern Exterior Ballistics", and the ISBN is 0764307207.
HTH,
SAB