Free fall under vacuum, Stokes drag, and quadratic drag

What you are seeing: three identical balls dropped from the same height at $t = 0$. The yellow one experiences no drag (vacuum, $\dot v = -g$); the cyan one experiences Stokes drag ($\dot v = -g - b v$, linear in velocity); the orange one experiences quadratic drag ($\dot v = -g - c |v| v$). They land at different times and arrive with different velocities.

The right-side plot tracks $|v(t)|$ for each ball. Vacuum is a straight line $|v| = g t$. Stokes asymptotes to its terminal $v_t = mg/b$ exponentially. Quadratic asymptotes to $v_t = \sqrt{mg/c}$ on a slower-than-exponential approach (think $\tanh$ shape). Crossover between the two drag laws happens at $v_c = b/c$: above this speed quadratic drag dominates, below it Stokes dominates.