= Viscous damping
{title2=$F_{\mathrm d}=-b\dot x$}
<Viscous damping> means a <force> proportional to, and opposite to, <velocity>: $F_{\mathrm d}=-b\dot x$ with $b\geq0$. Its coefficient has units $\mathrm{kg\,s^{-1}}$, equivalently $\mathrm{N\,s\,m^{-1}}$. The name describes a <force> law; <eddy-current damping> can approximate the same law without a viscous fluid. Constant $m$, $b$ and $k$ produce a <linear ordinary differential equation>, allowing <superposition> of responses. <Kinetic friction> with approximately constant magnitude and <quadratic drag> obey different laws, so their decay need not have the <exponential decay> or critical threshold derived here.
Back to article page
