Compression waves and kinetic energy losses in collisions between balls and rods of different lengths

• Published in: American journal of physics Vol. 82; no. 4; pp. 280 - 286
• Main Authors: Freschi, A. A., Hessel, R., Yoshida, M., Chinaglia, D. L.
• Format: Journal Article
• Language: English
• Published: Woodbury American Institute of Physics 01-04-2014
• Subjects: Collisions; Kinetics; Materials elasticity
• ISSN: 0002-9505; 1943-2909
• DOI: 10.1119/1.4864273

We report investigations of collisions between steel balls and free-ended rods using an electro-mechanical apparatus combined with a Michelson interferometer. Our experimental methodology allows for the evaluation of several collision-initiated parameters, such as collision duration, speed of the inter-material wave pulse, change in rod length, and post-collision center-of-mass velocity. The fractional loss of kinetic energy of the ball-rod system is studied theoretically and experimentally as a function of the rod length. Results are compared to predictions obtained from the elastic-body collision theory. Several aspects of elastic waves are illustrated without recourse to complicated mathematics. The experiment provides significant insight into the physical behavior of colliding solids.