[From Bruce Abbott (2015.02.11.1155 EST)]
There’s an elementary but informative introduction to dynamical systems by Louis Goldstein available on the net in pdf format at
http://sail.usc.edu/~lgoldste/ArtPhon/Presentations/Dynamics%20Intro.pdf . I bring this particular example up because it uses the mass-spring-damper model as an example. The paper covers the numerical versus analytical approach, gives the simulation code, provides graphs showing how various factors affect the mass-spring-damper system, and even discusses phase-space attractors such as I illustrated in the screen-shot of my mass-spring-damper simulation.
Goldberg asserts that the mass-spring-damper system includes feedback, by the way.
Bruce