"FWIW, describing a baseball's arc is not a trivial calculation in the real world."It really depends on what you are after and what accuracy you require.
If you are interested in how far the ball will fly, or how high up it will go, when tossed by a outfielder at a certain angle and initial speed then equations from high school physics will get you fairly close. If you want to know how the baseball moves when thrown by a knuckle ball pitcher then even a super computer will probably not get you an accurate answer.
When I talk about simple models for closed box and bass reflex enclosures then the results will be reasonably accurate for small signal inputs and using the rest of the assumptions that come with a Thiele/Small type of model/analysis. This is how I operate my stereo system most of the time. If you are talking about high input signals driving the driver into the nonlinear range then the simple model's accuracy will suffer.
However, in my opinion and within my experience the simple models do an excellent job of describing the behavior of a baseball's trajectory and a speaker's low frequency performance. Sometimes people overcomplicate problems and the result is they never get a decent usable answer. I had a manager that used to preach "Better is the enemy of good enough!". But there are always people (engineers in particular) who dive right into rocket science when it is really not required.
Martin