Posted by grim (206.162.192.40) on May 28, 2003 at 00:12:52:
In Reply to: Reference frames posted by Rob on May 27, 2003 at 23:17:01:
: That's certainly a different way of looking at things! I've been looking at Bessler's wheel from a different point of view, and I think it's making me more skeptical of the whole idea:
: We all look at the wheel as rotating about a stationary axle. But what if we take the wheel off its supports and let it roll along the ground? We can easily envision the wheel rolling along, as long as it is on a downward slope. It is harder to imagine the wheel rolling along continuosly on a flat and level plane (a flywheel with no friction maybe). But Bessler's wheel supposedly did actual work - can we imagine a wheel rolling itself up-hill all by itself? It's not using gravity, it's defying gravity. Perhaps someone will come up with a good idea by trying to get a wheel to roll up-hill, but it seems like an impossibilty to me. Sorry I may sound a little "David-ic"
There's several grade school demos on 'COG' that use a hoop, inclined plane and a weight. The hoop is set at the bottom of the incline and a weight is attached to the inside of the hoop at the two o'clock position. When released, the weight seeks its 'punctum quietus' and causes the hoop to roll uphill on the inclined plane. The hoop isn't defying gravity, the weight is doing work on it while seeking its lowest possible balance point.
Regards
grim