Re: shifting one's weight

[guntbert@cut.big.ac.at (Guntbert Reiter)]

*"Re: shifting one's weight"*
James Mclean wrote on Thu, 6 Feb 1997 14:25:17 -0800 (PST) :

> This is in error.  If you will notice, it is also possible for the =
see-saw
> to tip in one direction as the mass extends in the other direction such
> that the CoM would remain above the pivot.=20

But the only way to shift the see-saw's CoM in a *remarkable*
amount is to move the whole thing: be C .. CoM, P .. pivot, Alpha
... angle(see-saw, horizont), h=3Dd(CP)<10cm, Alpha<30deg, then
deltaX<2*(10cm*sin(30deg))~5cm. I suppose even a soldier kept at
"attention" will shift his CoM in a greater amount.

This reminds me of another gag regarding com and stability: Let
your students stand upright with their back touching a wall and
then tell them to fasten their bootlaces ... ;-))

Bye, bye
	Guntbert
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+please correct me, if I misuse some technical terms+
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Mag. Guntbert Reiter, Graz, Austria
teacher for physics and mathematics
e-mail     : guntbert@cut.big.ac.at