At 00:12 7/9/99 -0400, Martin Jagersand wrote:
>The question question is does the 25 campers parked on the middle
>of the bridge make the mass centrum of the bridge (alone) move
>up or down?

Well, I have trouble seeing how loading a flexible object with a mass could
make the center of mass of the original object move *up* (or as B. Fuller
would have said, *out*).  The load is on the middle of the span, the span
goes down, the cables stretch, the catenary cables straighten out a little
on both sides of the towers.  Be darned, maybe it does move up.  Maybe it
stays in the same place.  But 25 Westys is too big a load for a
gedanken-experiment.  How about one Westy Camper Manual?

Ok, Martin, I'll bite.  I say it moves up.  A little.

david
David Beierl - dbeierl@ibm.net