= Terminal velocity
{title2=$\mathbf v_T$}
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<Terminal velocity> is a constant limiting <velocity> approached when a <velocity>-dependent resistance balances the other applied <forces>. A falling body may keep moving while its net <force> and <acceleration> tend to zero. For downward motion in a stationary medium, its limiting <speed> is set by balancing <gravitational weight> against <drag force>, including <buoyancy> if appreciable. The balance, rather than a universal numerical value, is the defining idea. https://openstax.org/books/university-physics-volume-1/pages/6-4-drag-force-and-terminal-speed[Ling, Sanny and Moebs, section 6.4: drag and terminal speed]{ref}
The <terminal velocity under linear drag> gives a simple example with an explicit approach to the limit. Real falling objects need an appropriate resistance model: <linear drag> is useful for slow motion of a small sphere in <Stokes flow>, whereas many faster falling objects require <quadratic drag>. Changing <mass> also changes the question: the existing <accreting raindrop with quadratic drag> has a <speed-radius attractor of an accreting raindrop>, rather than the fixed-<mass> balance used below.
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