True velocities of particles from an ﹩\Omega _{m}=1﹩, CDM, cosmological N‐body simulation, compared to the velocities predicted by linear theory from the mass‐density field after it is smoothed with Gaussian filters of radius ﹩R_{s}=3﹩, 5, 10, and 15 h⁻¹ Mpc (panels a, b, c, and d, respectively). The points show one Cartesian component of the particles’ velocities. Solid lines show the relation ﹩\boldsymbol{v}_{\mathrm{true}\,}=\boldsymbol{v}_{\mathrm{pred}\,}﹩.