March 2020 Issue,
Volume 88, No. 3
Misconceptions about gyroscopic stabilization https://doi.org/10.1119/10.0000517
A spinning gyroscope resists small torques in directions perpendicular to its axis, that is, the angular orientation of a body rigidly attached to a gyroscope is stable against rotation around certain axes. Since the angular orientation of a body is described by three angles (e.g., Euler angles), one might conclude that it is possible to stabilize the orientation of an object against rotation using a combination of three gyroscopes spinning around non-collinear axes. We perform experiments under conditions of weightlessness to demonstrate that systems of coupled gyroscopes cannot arrest the angular orientation of free-floating objects, in contradiction to a widespread myth about gyroscopic stabilization, based on the above arguments.
Uranium fission and plutonium production in the undergraduate lab by Jos van Willigen, Casper Loman, Pjotr Thibaudier, David B. R. A. Fokkema and Tom W. Hijmans. DOI: American Journal of Physics 88, 200 (2020); https://doi.org/10.1119/10.0000206
Dynamics of a round object moving along curved surfaces with friction by Gabriel M. Mejía, Jose M. Betancourt, Christian D. Forero, Nicolas Avilán, F. J. Rodríguez, L. Quiroga and Neil F. Johnson. DOI: 10.1119/10.0000310
Assessing randomness with the aid of quantum state measurement by Mathew R. Coleman, Kaylin G. Ingalls, John T. Kavulich, Sawyer J. Kemmerly, Nicolas C. Salinas, Efrain Venegas Ramirez and Maximilian Schlosshauer. DOI: 10.1119/10.0000383
Photons: The History and Mental Models of Light. Klaus Hentschel. 244 pp. Springer International Publishing, 2018. Price: $78.23 (hardcover). ISBN 978-3-319-95251. (Eugene Hecht, Reviewer.) . DOI: 10.1119/10.0000611