Quadratic air resistance
Drag $cv^2$: coasting as $v_0/(1 + t/\tau)$, falling as $v_{\text{ter}}\tanh(gt/v_{\text{ter}})$ with $v_{\text{ter}} = \sqrt{mg/c}$, and why two-dimensional motion must be integrated numerically.
About 35 minutes8 activities Paper packet