We discuss a project on rigid-body motion that is appropriate for students in an upper-division course in classical mechanics. We analyze the motion of Hurricane Balls, two spheres that are welded (or glued) together so they act as a single object that can be spun like a top. The steady-state motion consists of purely rotational motion about the center of mass, such that only one ball is in contact with the table as it rolls without slipping. We give a qualitative explanation for why one ball rises into the air, and we theoretically analyze the system using multiple approaches. We also perform a high-speed video analysis to obtain experimental data on how the orientation depends on the spin rate, and find agreement within a few percent of the theory.

Jackson, David P., David Mertens, and Brett J. Pearson. Hurricane Balls: A Rigid-Body-Motion Project for Undergraduates. American Journal of Physics 83, no. 11 (2015): 959-968. https://aapt.scitation.org/doi/full/10.1119/1.4930087

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