title: Dynamics of shallow impact cratering.
abstract: We present data for the time dependence of wooden spheres penetrating into a loose noncohesive packing of glass beads. The stopping time is a factor of 3 longer than the time d/v0 needed to travel the total penetration distance d at the impact speed v0. The acceleration decreases monotonically throughout the impact. These kinematics are modeled 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.
authors.affiliation: Department of Physics and Astronomy, University of California, Los Angeles, California 90095-1547, USA.
authors.forename: M A
authors.initials: MA
authors.lastname: Ambroso
authors.forename: R D
authors.initials: RD
authors.lastname: Kamien
authors.forename: D J
authors.initials: DJ
authors.lastname: Durian