{"472491":{"#nid":"472491","#data":{"type":"event","title":"Non-holonomic stability and rotation with zero angular momentum: Demonstrations of stability and of the falling cat phenomenon go sour","body":[{"value":"\u003Ch5\u003ESchool of Physics Nonlinear Science \u0026amp; Mathematical Physics Seminar: Prof. Andy Ruina, Cornell University\u003C\/h5\u003E\u003Cp\u003ETwo classes of (interesting, at least to me) physical behavior follow from the impossibility of integrating some formulas that involve derivatives. First, systems with wheels or ice skates can be conservative yet have asymptotic stability. This is relevant to braking cars, flying arrows and the balance of skateboards and bicycles. Second, is the well known possibility that a system with zero angular momentum can, by appropriate deformations, rotate without any external torque. This effect explains how a cat that is dropped while upside down can turn over and of how various gymnastic maneuvers are performed. Both rolling contact and constancy of angular momentum are examples of the \u0022non-integrability\u0022 of a \u0022non-holonomic\u0022 equation. There are various simple demonstrations of these phenomena that can go bad. Cars can crash, bikes fall over and, in terrestrial experiments, various effects can swamp that which one wants to demonstrate. The talk describes the basic theory and then a collection of simple experiments that fail various ways for various reasons.\u003C\/p\u003E","summary":null,"format":"limited_html"}],"field_subtitle":"","field_summary":"","field_summary_sentence":[{"value":"Non-holonomic stability and rotation with zero angular momentum: Demonstrations of stability and of the falling cat phenomenon go sour"}],"uid":"27664","created_gmt":"2015-11-23 11:25:42","changed_gmt":"2017-04-13 21:17:36","author":"Alison Morain","boilerplate_text":"","field_publication":"","field_article_url":"","field_event_time":{"event_time_start":"2015-12-04T15:00:00-05:00","event_time_end":"2015-12-04T16:00:00-05:00","event_time_end_last":"2015-12-04T16:00:00-05:00","gmt_time_start":"2015-12-04 20:00:00","gmt_time_end":"2015-12-04 21:00:00","gmt_time_end_last":"2015-12-04 21:00:00","rrule":null,"timezone":"America\/New_York"},"extras":[],"groups":[{"id":"126011","name":"School of Physics"}],"categories":[],"keywords":[{"id":"148811","name":"Non-holonomic stability and rotation"}],"core_research_areas":[],"news_room_topics":[],"event_categories":[{"id":"1795","name":"Seminar\/Lecture\/Colloquium"}],"invited_audience":[{"id":"78751","name":"Undergraduate students"},{"id":"78761","name":"Faculty\/Staff"},{"id":"174045","name":"Graduate students"}],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cp\u003E\u003Ca href=\u0022mailto:amorain@gatech.edu\u0022\u003Eamorain@gatech.edu\u003C\/a\u003E\u003C\/p\u003E","format":"limited_html"}],"email":[],"slides":[],"orientation":[],"userdata":""}}}