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Re: The Olympics



At 15:50 25/09/00 , Michael Edmiston wrote:

All of this is perfectly clear, but Doug's comment I replied to suggested
simply that in free fall one can achieve *neither* a net displacement nor
rotation in the absence of an external push. I'm pointing out that while
this is true for translational motion, it's not true for rotational motion.
You *can* achieve a net rotation while maintaining zero angular momentum,
the difference being that you can play around with I but not m.


Howdy,

It isn't true for translational motion either; throw part of the
object in one direction and the rest will move in the opposite
direction in such a way that the momentum of the system is conserved
(zero relative to the CM). Where did that energy come from? the
internal energy stored in the body (internal batteries, exothermic
chemical reactions, etc.)

Good Luck,
--
Herb Schulz
(herbs@interaccess.com)