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Conference rusure::math

Title:Mathematics at DEC
Moderator:RUSURE::EDP
Created:Mon Feb 03 1986
Last Modified:Fri Jun 06 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:2083
Total number of notes:14613

468.0. "Rolling things" by CLT::GILBERT (Juggler of Noterdom) Tue Apr 08 1986 04:52

I have a circular disk and an elliptical disk, and I'm going to roll
them both down an incline.  Assuming the circumferences are the same,
they should both move along the incline at about the same average rate.
Right?
T.RTitleUserPersonal
Name
DateLines
468.1ENGINE::ROTHTue Apr 08 1986 11:369
No, their moments of intertia will differ, and the ellipse could clearly
be in a stable position depending on its eccentricity and the slope of the
incline, it would have to depend on the amount of push you gave them also.
The ellipse could lose contact with the incline...

By conservation of energy, if the ellipse and circle had the same moment of
intertia they would have the same 'average' rate of motion down the incline.

- Jim
468.2CLT::GILBERTJuggler of NoterdomTue Apr 08 1986 23:242
    Does an ellipse have the same moment of inertia as a disk of the
    same circumference?