| Topic: |
Science > Physics |
| User: |
"" |
| Date: |
12 Aug 2005 08:35:02 AM |
| Object: |
energy |
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| User: "Strange Indeed" |
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| Title: Re: energy |
12 Aug 2005 08:54:01 AM |
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wrote in news:1123853702.057460.28010@f14g2000cwb.googlegroups.com:
What is energy?
http://wordnet.princeton.edu/perl/webwn?s=energy
"S: (n) energy ((physics) the capacity of a physical system to do work;
the units of energy are joules or ergs) 'energy can take a wide variety
of forms'"
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| User: "James Copeland" |
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| Title: Re: energy |
12 Aug 2005 08:43:06 PM |
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"Strange Indeed" <strange@none.com> wrote in message
news:Xns96B073318307Cstrangenonecom@63.223.5.248...
zomoco1@comcast.net wrote in
news:1123853702.057460.28010@f14g2000cwb.googlegroups.com:
What is energy?
http://wordnet.princeton.edu/perl/webwn?s=energy
"S: (n) energy ((physics) the capacity of a physical system to do work;
the units of energy are joules or ergs) 'energy can take a wide variety
of forms'"
This is the common, pat definition of energy, but it is incomplete. Atoms
and molecules possess zero point energy, which is energy they have even at
absolute zero, and it cannot be lost; hence it cannot be transformed into
work. For example, the zero point of vibrational energy of a simple diatomic
molecule is (1/2)hf > 0, where h is Planck's constant and f is the
vibrational frequency. The molecule will have this residual energy even at 0
K, and there is no way in which this energy can be taken from it. These are
quantum mechanical consequences which reflect Heisenberg's Uncertainty
Principle. I.e., in the case of vibration, if the vibrational energy were to
be zero, the atoms would not be moving and would have zero momentum. So we
could simultaneously know exactly both the position coordinate (the bond
length which would be fixed) and the momentum (zero, since the atoms are not
moving with respect to one another). Heisenberg's Principle would have been
violated.
Jim C.
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| User: "Sam Wormley" |
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| Title: Re: energy |
12 Aug 2005 08:51:05 AM |
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wrote:
What is energy?
http://mathworld.wolfram.com/Energy.html
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| User: "John Sefton" |
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| Title: Re: energy |
12 Aug 2005 10:09:58 AM |
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wrote:
What is energy?
spin
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| User: "Sam Wormley" |
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| Title: Re: energy |
12 Aug 2005 07:07:12 PM |
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John Sefton wrote:
spin
Out of the responses in this thread "What is Energy", John, yours
doesn't qualify as a good answer. Flush!
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| User: "PD" |
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| Title: Re: energy |
12 Aug 2005 12:11:33 PM |
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wrote:
What is energy?
What is a zebra?
You would answer that question by characterizing its properties.
Energy is an attribute that we associate with states (configurations of
physical systems) that has a peculiar numerical property: it is fully
accountable. That is, in any system that does not transact outside of
itself, the amount of energy stays the same, regardless of what happens
inside. If the system does transact with something outside of it, we
can draw another system boundary around the two of them, and the energy
of that enlarged system will stay the same. In more common terms:
gozinta = gozouta.
The fact that it is numerically quantifiable means that we can
calculate it, both for systems and (more importantly) for transactions,
which is enormously helpful in predicting the behavior of physical
systems.
But if you're asking, but what IS it, fundamentally? Then, I'd look at
the above and say, other than that, not much. What IS a dollar,
fundamentally?
By the way, it is not the only attribute that behaves this way.
PD
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