Runge Kutta for Game Physics

So I'm working on building a physics simulator in Java.  I did well in the AP physics class back in high school, and aced the algebra-based physics classes at Georgia State, but implementing them into a program was a little different (due to the need to know and update all properties at any time, as opposed to calculating one or two unknowns from a set of known values).  So, of course, I started searching the internet for solutions.

Image via Wikipedia

Anyway, while researching I stumbled across a really neat article on something called Runge Kutta order 4, or simply RK4.  It's a method of approximating the solutions to differential equations, and was invented (or developed, if you rather) around the start of the 1900s by, you guessed it, two mathematicians name Runge and Kutta.  So here is the full article for those of you interested in game physics; check it out!

The article does a wonderful job of explaining how RK4 works by stripping away all of the mathematics that might scare potential learners out there, so if you feel as though you might be in that group, check it out anyway!