  We present data for the time-dependence of wooden spheres penetrating into a
loose non-cohesive packing of glass beads. The stopping time is a factor of
three longer than the time $d/v_\circ$ needed to travel the total penetration
distance $d$ at the impact speed $v_\circ$. The acceleration decreases
monotonically throughout the impact. These kinematics are modelled by a
position- and velocity-dependent stopping force that is constrained to
reproduce prior observations for the scaling of the penetration depth with the
total drop distance.
