Date of download: 10/14/2017 Copyright © ASME. All rights reserved. From: Three-Dimensional Modeling and Simulation of a Falling Electronic Device J. Comput. Nonlinear Dynam. 2006;2(1):22-31. doi:10.1115/1.2389039 Figure Legend: Numerical results for multiple collisions of the model cell phone with the ground. Initial contact angle θ=2deg, initial angular velocity ω=0, initial elevation of center of mass zc∣t=0=1, ground stiffness kG=108, ground damping coefficient cG=107, friction coefficient μk=0.075. (a) Normal impact contact force as a function of time; (b) total energy, kinetic energy, and potential energy as a function of time.