# Typical examples of second order nonlinear dynamic systems

## Main Question or Discussion Point

Hi guys,
after hours of searching internet I couldn't find much real-life examples of second order nonlinear dynamic systems (only tons of tons of equation and system theory... got totally frustrated). They will serve as a base process for modeling controllers.
So far I found propeller pendulum and water tank / heating system.
I need some more ideas. Thanks

$\frac{d^2T}{dx^2}- \frac{dT}{dx}= A\cdot e^{C \cdot T}$