Gravitational waves emitted during the inspiral, plunge and merger of a black
hole binary carry linear momentum. This results in an astrophysically important
recoil to the final merged black hole, a ``kick'' that can eject it from the
nucleus of a galaxy. In a previous paper we showed that the puzzling partial
cancellation of an early kick by a late antikick, and the dependence of the
cancellation on black hole spin, can be understood from the phenomenology of
the linear momentum waveforms. Here we connect that phenomenology to its
underlying cause, the spin-dependence of the inspiral trajectories. This
insight suggests that the details of plunge can be understood more broadly with
a focus on inspiral trajectories.Comment: 15 pages, 12 figure
