Abstract
We study fixed assemblies of touching spheres that can individually rotate. From any initial state, sliding friction drives an assembly toward a slip-free rotation state. For bipartite assemblies, which have only even loops, this state has at least four degrees of freedom. For exactly four degrees of freedom, we analytically predict the final state, which we prove to be independent of the strength of sliding friction, from an arbitrary initial one. With a tabletop experiment, we show how to impose any slip-free rotation state by only controlling two spheres, regardless of the total number.
- Received 15 February 2016
DOI:https://doi.org/10.1103/PhysRevLett.116.254301
© 2016 American Physical Society
Physics Subject Headings (PhySH)
Focus
Balls as 3D Gears
Published 24 June 2016
Spinning a few spheres among a large collection of them can lead to a predictable state where each sphere rotates in synch with the others.
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