Special Math. Phys. Seminar by
Stephen Sontz scheduled for Monday the 24th is cancelled


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Tadashi Tokieda
    arrive     Wed 12:48p CHO airport
    talk       Wed  3:30p in 317 Kerchof
    staying    with Greg Arone 
    leave      Friday afternoon for DC.

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Math. Phys. Seminar  *  Wed September 26  *  317 Kerchof Hall

        Tadashi Tokieda (UQaM)
        "Sound of a spinning penny".


 Spin a penny on a table.  It wobbles and wobbles, and 
 when it eventually shudders to an abrupt halt, it emits 
 a whirring sound whose pitch seems to go to infinity^*.  
 Though the theory of a disc moving on a plane dates back 
 to Euler (1765), this divergence has never been explained.  
 In NATURE, vol. 404 (2000) 833, Moffatt attributed it to 
 the effect of the air trapped under the disc, causing no 
 little controversy.  In this talk I should like to give 
 an (almost) exact solution to the problem which exhibits 
 the divergence.

 [^* With a penny, we cannot hear this very well.  But
 a special toy with a striking finish will be demonstrated 
 at the talk.]