Since I've been enjoying the topics and discussions of this news group, and I see that there are many posters who are quite bright, I decided to pose a question concerning the laws of physics to stimulate the group's curiosity.
The question is: If you hang two plumb bobs, say 50 feet apart are the strings parallel?
I would say they are as close to parallel as one would care for them to be. If you want to get technical, they are not exactly parallel due to the curvature of the earth. One would assume that the bottom of the plumb bob is pointing at the exact centre of the earth due to gravity and since we're on a ball, they wouldn't be exactly parallel. At 50 feet apart, the difference wouldn't be enough to care about.
Theoretically, no, but I doubt if you could measure the difference if they were just 50 feet apart. If the 2 bobs were, say, a couple thousand miles apart, they'd both be pointing towards the center of the earth, so they definitely wouldn't be parallel. Isn't that the principle that led to the first calculations of the earth's diameter? Some guy looking down wells... OK, google tells me it was Eratosthenes, in Alexandria. Andy
You guys are right on the money. I'll have to thinks up a harder question if I hope to stump the group.Joe G
Ok then... In recent news;
*** In a recent study, mathematician George Sparling of the University of Pittsburgh examines a fundamental question pondered since the time of Pythagoras, and still vexing scientists today: what is the nature of space and time? After analyzing different perspectives, Sparling offers an alternative idea: space-time may have six dimensions, with the extra two being time-like. ***So if I turn a six dimensional bowl on my quantum lathe, primarily taking advantage of the additional time-like dimensions, how long do I have to work the finish in before it dries?
Two answers: A1) No, since each will hang toward the center of the earth (ignoring gravitational pulls of other less massive or more distant bodies).
A2) Yes, if the correctness of the answer is going to be determined by empirical methods using measurement tools available to the average homeowner.
Hell, to hear the way some folks around here talk, you'd think their table saws were adjusted to tighter tolerances than the differences between those two plumb bobs. :-)
That one is ridiculously easy..... It depends on what rpm you're running the lathe.
OK, here is a wreck answer.
They would be parallel if it could be measured by a fifty foot rule from Lee Valley. (Rob Lee, here is an idea for you next April 1st tool)
BTW how parallel is string anyway? Any horizontal measurement of a vertical string would change its position.
how's about if there was no limit to the length of the string? wow how long is a string? i'd say that half way to the middle is one fourth the way to the other end.
At high tide, anyway.
Russ wrote in news:3h7Wh.1980$np4.1820 @bignews4.bellsouth.net:
Did you soak it in LDD?
No. Both will point toward the center of gravity (somewhere inside the earth).
So *that's* what's causing my kickbacks??? The earth's curvature? Knew it had to be something.
jc
Nope. I'm getting about a 1/2 second of arc between them.
Since you are probably working in imaginary time, I'd say the finish was on the piece even before your first cut. So don't worry about it.
dwhite
They would sure appear to be parallel and for all practical purposes would be, but in truth they would be between 1 and two ten-thousanths of a degree off.
Lee
The finish goes on FIRST, fool.
If we are going to split hairs then:
The error from the theoretical parallels would vary both with altitude and location on the globe. A geodesic error will cause different errors on the two strings as the earth is not a perfect sphere.
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.