...Examples include natural decay, temperature change, free-fall against air drag, capacitor (dis)charge, or a spring-mass oscillation "playing catch" between its two energy forms. Higher-order systems can often simplify into 1st- or 2nd-order frames when a slower element dominates. Many solutions take the forms of exponential envelopes, sinh-cosh-tanh hyperbolics, and sine wave oscillations. (read more)