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Stone Shifting 2

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GordonP G
GordonP Aug 26, 2003 19:06:13
Replying to nigelswift

OK Guys I've nearly got my head right so.

The side force only comes into play when the stone starts to slip down the tower, but the rotational force that has built up in the stone means that this slipage only ocurrers for a short period so that as the rotatioal force takes the top half of the stone away from contact with the tower we're OK again. Steves long wooden lath would not have been heavy enough to build up much rotational force so it pushed the tower over.

In the experiment I did with the 4 ton block the pallets only moved a matter of inches. If we buttress the tower to hold the force for a second or so the little bit of slippage we get will probably take some of the rotational force out of the stone and make it work better.

The good news I was on about earlier, I've had a word with the manager of the museum and he has promised to get in touch with the manager of the quarry which is on the same site with a view to them supplying some land and a ten ton stone. He was pretty confident of the result.

S Steve Gray
Steve Gray Aug 26, 2003 19:27:24
Replying to GordonP

I think that the slipping should be much more predictable with a large stone than with a small one. The sheer weight should be enought to overcome minor surface effects. From the computer model it should be possible to allow for the slippage and still hit the hole.

However, one idea to avoid the problem might be to lash the block to the topmost log of the tower (I call this the pivot log) so that the log rotates with the block. This would keep the block from falling before it strikes the edge of the hole. Once it does, the rotational momentum would pull the log out of the tower as the block moves into it's upright position. It's easier to draw it thanto describe it.

Anyway I have to go out now, I'll check in later this evening.