Subject:
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Curses! Partially foiled! (was: Darn those definitions (was: The new Super Car))
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Newsgroups:
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lugnet.robotics
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Date:
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Fri, 6 Aug 1999 17:15:43 GMT
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Original-From:
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John A. deVries II <zozzles@lanl=saynotospam=.gov>
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Viewed:
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1154 times
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At this point, I wonder if this thread could be made hugely more valuable
to the LEGO-robotics community: I wonder if anyone would like to write up
a short bit about mass-dashpot-spring suspensions and why they are useful
from a viewpoint larger than "it is more comfortable to ride in a
well-suspended car"... (for example.) Please?
I realize that our robots are moving slowly enough to not be bothered by
resonant frequencies and all that, but a decent suspension might make all
the difference if you were creating something like the soda-can collector
but where your target is moving -- you wouldn't want your 'claw' to be
bobbling about & you can't just stop to snatch things.
Oh yeah -- "linear resistance" -> friction. Obviously my background is
electronics, eh?
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> You're both right. Fluid isn't a state of matter. Glass is fluid, as is air.
Ok, you are literally correct in the sense that "fluid" has an intermediate
etymology (Latin) of "to flow" and both liquids and gases can flow, but an
earlier etymology is from the Greek and means "to boil over" ... I've never
seen gases boil. Nonetheless, hydraulics and pneumatics are different:
consider this -- liquids are rarely (appreciably) compressible whereas all
gases follow Boyle's/Charles' law... you know, good old PV=nRT and all that
jazz.
BTW: the notion that glass is a fluid has been deprecated, in spite of the
fact that it is still considered an amorphous liquid. I'm fairly certain
that experiments have shown no measurable flow and that the old "evidence",
i.e. old glass windows being thicker at the bottom than the top has been
shown to be a documented craftsman's technique of making things stronger --
the usual idea of having the base be as wide (think pyramids) as possible.
However, I apologize for putting this in 'cuz it is SO far off-topic.
But hey, its all words, yes?
Regards,
Zoz
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John A. deVries II
zozzles@lanl.gov
--
Did you check the web site first?: http://www.crynwr.com/lego-robotics
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Message is in Reply To:
 | | Darn those definitions (was: The new Super Car)
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| (...) Wrong-o. Sorry to be flameish about this, but generally speaking (approximately) four states of matter are accepted: solid, liquid, gas and plasma. Liquids and gases have fairly distinct differences having to do with the degree of (...) (25 years ago, 6-Aug-99, to lugnet.robotics)
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