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pochas
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 Posted: Thu Dec 25, 2003 12:42 am Post subject: Re: What is the definition for Energy ? |
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In article <3FE9BA54.70302F4A@mtf.ntnu.no>, Ivar S.
=?iso-8859-1?Q?Ertesv=E5g?= <ivar.s.ertesvag@mtf.ntnu.no> wrote:
[quote]Don Lancaster wrote:
T Rex wrote:
Looked thru the web.
Unable to find a good site that defines or explian energy.
Mayve I did not get to see the right sites.
One site says that Energy cannot be defined or described.
All attempts on giving a brief and general definition on energy can be
questioned.
[/quote]
Energy is the potential for doing work.
Work is the application of force over a certain distance.
"Useful work" depends on how one defines the problem.
E=MC2 doesn>t change anything. Matter contains only so much
energy. You can fuse elements until you get iron, or you can
fission heavy elements until you get iron. That>s why there is
so much iron around. |
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Ivar S. Ertesvåg
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| Posted: Thu Dec 25, 2003 3:32 am Post subject: Re: What is the definition for Energy ? |
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pochas wrote:
[quote]
In article <3FE9BA54.70302F4A@mtf.ntnu.no>, Ivar S.
=?iso-8859-1?Q?Ertesv=E5g?= <ivar.s.ertesvag@mtf.ntnu.no> wrote:
Don Lancaster wrote:
T Rex wrote:
Looked thru the web.
Unable to find a good site that defines or explian energy.
Mayve I did not get to see the right sites.
One site says that Energy cannot be defined or described.
All attempts on giving a brief and general definition on energy can be
questioned.
Energy is the potential for doing work.
[/quote]
A statement doesn>t become more true just by repeating it. |
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Don Lancaster
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| Posted: Thu Dec 25, 2003 4:57 am Post subject: Re: What is the definition for Energy ? |
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"Ivar S. Ertesvåg" wrote:
[quote]
Energy is the potential for doing work.
A statement doesn>t become more true just by repeating it.
[/quote]
But the FACT that it is in virtually EVERY physics test DOES make it a
lot MORE true.
--
Many thanks,
Don Lancaster
Synergetics 3860 West First Street Box 809 Thatcher, AZ 85552
voice: (928)428-4073 email: don@tinaja.com fax 847-574-1462
Please visit my GURU>s LAIR web site at http://www.tinaja.com |
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Ivar S. Ertesvåg
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| Posted: Thu Dec 25, 2003 5:04 am Post subject: Re: What is the definition for Energy ? |
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Don Lancaster wrote:
[quote]
"Ivar S. Ertesvåg" wrote:
Energy is the potential for doing work.
A statement doesn>t become more true just by repeating it.
But the FACT that it is in virtually EVERY physics test DOES make it a
lot MORE true.
[/quote]
The 2nd law was formulated in the early 1850s: Some energy can not
be used for doing work. Which tests contradict this?
cf. my questions to your former posting. |
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T Rex
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| Posted: Thu Dec 25, 2003 6:20 am Post subject: Re: What is the definition for Energy ? |
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Don..hope you can explain this.
Consider a mass = M units.
Take the equation E=mc^2
Which says that the Energy = mass times square of velocity of light.
Now, this velocity of light is 300,000,000 meters / second.
The unit of time is in seconds.
This unit of time is derived from a 24 hour day period. 24x60x60 =
86,400 seconds.
For all we know, the figure 24 hours / DAY is an arbitarily set
figure. ( Imperial units ? )
i.e: The DAY could have been divided into 100 hours with each hour
equal to 100 minutes and each minute equal to 100 seconds. ( metric !!
)
Thus one DAY would equal 100,00,000 ( metric SECONDS ).
What would be velocity of light in terms of this metric second ?
Approx 26,000,000 meters / second.
Now using the equation E=mc^2, if the same mass M is translated into
energy units, using this metric second, then the quantity of energy
within this mass M is very much lower.
Meaning that the same mass M has a different capacity or capability to
do work.
What if the time unit ( second ) was made arbitarily much larger than
what it is now ?
The same mass M can have much larger capacity to do work.
In fact it appears that this capacity can be infinite depending on how
one set the basic time unit to calibrate light velocity.
Somewhere there has to be an element of ' an independant/absolute
time factor ',. Yes ?
Where is the catch Don ?
Many thanks for yout time.
Merry Christmas
Don Lancaster <don@tinaja.com> wrote in message news:<3FE8A75C.FA0D28B2@tinaja.com>...
[quote]T Rex wrote:
Looked thru the web.
Unable to find a good site that defines or explian energy.
Mayve I did not get to see the right sites.
One site says that Energy cannot be defined or described.
How do you respond when asked to define energy - by your
kid for example ?.
See http://www.tinaja.com/glib/energfun.pdf
Energy is the capacity or capability to do work.
Work is accomplished when a force moves something through a distance.
Power is the time rate of doing work.[/quote] |
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Don Lancaster
Guest
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| Posted: Thu Dec 25, 2003 6:55 am Post subject: Re: What is the definition for Energy ? |
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T Rex wrote:
[quote]
The same mass M can have much larger capacity to do work.
In fact it appears that this capacity can be infinite depending on how
one set the basic time unit to calibrate light velocity.
Somewhere there has to be an element of ' an independant/absolute
time factor ',. Yes ?
Where is the catch Don ?
[/quote]
The first catch is that you first have to assume non relativistic speeds
for classic physics.
The second catch is that you cannot consider energy by itself. You have
to simultaneously consider energy, entropy, and exergy.
What counts the most economically is exergy, or the thermodynamically
reversibly recoverable energy fraction.
See http://www.tinaja.com/glib/energfun.pdf
--
Many thanks,
Don Lancaster
Synergetics 3860 West First Street Box 809 Thatcher, AZ 85552
voice: (928)428-4073 email: don@tinaja.com fax 847-574-1462
Please visit my GURU>s LAIR web site at http://www.tinaja.com |
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H.J.
Guest
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| Posted: Thu Dec 25, 2003 12:08 pm Post subject: Re: What is the definition for Energy ? |
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Energy - A wee little bit of mass.
Mass - A whole crapload of energy.
"T Rex" <tee.rex@lovemail.com> wrote in message
news:73269c91.0312231225.5ed9661b@posting.google.com...
[quote]Looked thru the web.
Unable to find a good site that defines or explian energy.
Mayve I did not get to see the right sites.
One site says that Energy cannot be defined or described.
How do you respond when asked to define energy - by your
kid for example ?.[/quote] |
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Roland Paterson-Jones
Guest
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| Posted: Sat Dec 27, 2003 4:47 am Post subject: Re: What is the definition for Energy ? |
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"Don Lancaster" <don@tinaja.com> wrote in message
news:3FE8A75C.FA0D28B2@tinaja.com...
[quote]T Rex wrote:
How do you respond when asked to define energy - by your
kid for example ?.
Energy is the capacity or capability to do work.
Work is accomplished when a force moves something through a distance.
Power is the time rate of doing work.
[/quote]
Nope, energy is the capacity or capability to do work in outer space, where
the temperature is absolute zero.
'Exergy', on the other hand, is the capacity or capability to do work in any
particular normal situation.
Otherwise Don is right on the button.
Roland |
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Roland Paterson-Jones
Guest
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| Posted: Sat Dec 27, 2003 4:55 am Post subject: Re: What is the definition for Energy ? |
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"Don Lancaster" <don@tinaja.com> wrote in message
news:3FEA19D6.ABD27AC8@tinaja.com...
[quote]"Ivar S. Ertesvåg" wrote:
Energy is the potential for doing work.
A statement doesn>t become more true just by repeating it.
But the FACT that it is in virtually EVERY physics test DOES make it a
lot MORE true.
[/quote]
You>re all wrong. Energy and work are interchangeable. Much of modern
physics depends upon energy balance.
In fact all novel sources of energy, for example light (EM waves), nuclear
(e=mc^2) have been neatly incorporated into the 19>th century maxim of
conservation of energy.
Can the Don point us to the appropriate experimental evidence?
Should we consider conservation of energy, yet another house of cards?
Roland |
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Roland Paterson-Jones
Guest
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| Posted: Sat Dec 27, 2003 5:05 am Post subject: Re: What is the definition for Energy ? |
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"Don Lancaster" <don@tinaja.com> wrote in message
news:3FEA3576.39996189@tinaja.com...
[quote]T Rex wrote:
The same mass M can have much larger capacity to do work.
In fact it appears that this capacity can be infinite depending on how
one set the basic time unit to calibrate light velocity.
Somewhere there has to be an element of ' an independant/absolute
time factor ',. Yes ?
Where is the catch Don ?
[/quote]
Don, your answer is staggeringly weak:
[quote]The first catch is that you first have to assume non relativistic speeds
for classic physics.
[/quote]
Bullshit. e = mc^2 holds regardless of the units you measure. It is a
balanced equation whether you measure length in hair>s breadths, or time in
periods of Haley>s comet.
Your attempted answer shows a staggering misunderstanding of common physics.
[quote]
The second catch is that you cannot consider energy by itself. You have
to simultaneously consider energy, entropy, and exergy.
What counts the most economically is exergy, or the thermodynamically
reversibly recoverable energy fraction.
[/quote]
I have to assume that this is Kelly, the phone person at the end of Don>s
number.
Kelly, you really should ask Don before posting this garbage.
Roland |
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Mike Ackerman
Guest
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| Posted: Sat Dec 27, 2003 5:20 am Post subject: Re: What is the definition for Energy ? |
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Roland Paterson-Jones wrote:
[quote]Nope, energy is the capacity or capability to do work in outer space, where
the temperature is absolute zero.
'Exergy', on the other hand, is the capacity or capability to do work in any
particular normal situation.
[/quote]
WOW! At last an understandable definition for "exergy".
Mike Ackerman |
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Jerason Banes
Guest
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| Posted: Sun Dec 28, 2003 9:56 am Post subject: Re: What is the definition for Energy ? |
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cyril <meyn#ie#r.cy#ril@wan#adoo.fr//virezles#> wrote in message news:<pr9huvoc89m3agcvhamdje1lofrlb8rosb@4ax.com>...
[quote]Energy can be descibed as a "money" used to "buy" and "sell" natural
processes.
This definition is totally personnal and non-scientific :-)
[/quote]
A slightly more scientific definition that I like to keep in mind is
that energy is an attribute of the universe winding down. The same is
actually true for matter as well, but to keep it simple, we can think
of the universe as a bunch of rocks rolling down a hill. If you push a
rock ahead of you, it speeds up and you slow down. By doing this, you
effectively "unbalance" the current course of the rocks and create
what we think of as work.
Thus energy is the universe winding down.
Work is attempts to unbalance that energy in order to make something
useful happen.
How>s that? |
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Dan Bloomquist
Guest
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| Posted: Mon Dec 29, 2003 12:14 am Post subject: Re: What is the definition for Energy ? |
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Jerason Banes wrote:
[quote]cyril <meyn#ie#r.cy#ril@wan#adoo.fr//virezles#> wrote in message news:<pr9huvoc89m3agcvhamdje1lofrlb8rosb@4ax.com>...
Energy can be descibed as a "money" used to "buy" and "sell" natural
processes.
This definition is totally personnal and non-scientific :-)
A slightly more scientific definition that I like to keep in mind is
that energy is an attribute of the universe winding down...
[/quote]
That is an increase in entropy, not a definition of energy.
Best, Dan.
--
http://lakeweb.net
http://ReserveAnalyst.com
dbAtLakewebDotCom |
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Harry Conover
Guest
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| Posted: Mon Dec 29, 2003 2:21 am Post subject: Re: What is the definition for Energy ? |
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Dan Bloomquist <lakeweb@citlink.net> wrote in message news:<3FE8D8F1.2000802@citlink.net>...
[quote]T Rex wrote:
Looked thru the web.
Unable to find a good site that defines or explian energy.
Mayve I did not get to see the right sites.
One site says that Energy cannot be defined or described.
How do you respond when asked to define energy - by your
kid for example ?.
It sometimes gets confusing because there are many forms of energy.
Energy is defined. It is Force times Length in mechanics.
[/quote]
Sorry, Dan, but in physics that>s a definition of work. Energy by
contrast is the capacity to perform work.
Sorry to pick nit, but the precise definitions of fundamental units
work and energy, and the distinction between the two terms, is
critical to a clear understanding of basic mecanics.
To illustrate, the conversion n-joules of energy to n-joules of
accomplished work is impossible, since it would require a perfect
machine to accomplish. Perfect (100% efficient) machines don>t and
cannot exist.
On another note, I did like your example of the energy stored by the
water trapped behind a dam. Still, I believe it is important to point
out that that this stored potential energy is entirely derived from
the energy flux supplied by the sun, and gravity acts in essence only
in the capacity of a "spring" to store this captured solar energy.
Harry C. |
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Dan Bloomquist
Guest
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| Posted: Mon Dec 29, 2003 3:02 am Post subject: Re: What is the definition for Energy ? |
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Harry Conover wrote:
[quote]Dan Bloomquist <lakeweb@citlink.net> wrote in message news:<3FE8D8F1.2000802@citlink.net>...
T Rex wrote:
Looked thru the web.
Unable to find a good site that defines or explian energy.
Mayve I did not get to see the right sites.
One site says that Energy cannot be defined or described.
How do you respond when asked to define energy - by your
kid for example ?.
It sometimes gets confusing because there are many forms of energy.
Energy is defined. It is Force times Length in mechanics.
Sorry, Dan, but in physics that>s a definition of work. Energy by
contrast is the capacity to perform work.
[/quote]
Hi Harry,
Happy Holidays!
Well, maybe I have something to learn here, but let>s start with the
work-energy theorem and kinetic energy. Let>s force some mass through a
distance, what you say is not energy. Yet this mass now has an energy
equal to mv^2/2. If you>d like, work is transfer of energy from one
system to another. Transfer of energy means that this connection you
call work must be the same stuff as energy. You are not transferring
something else. It has the same dimensions in mathematical terms, so, it
is the same.
[quote]
Sorry to pick nit, but the precise definitions of fundamental units
work and energy, and the distinction between the two terms, is
critical to a clear understanding of basic mecanics.
[/quote]
Please show me the difference in the dimensional system. Or, if you>d
like, explain the difference.
[quote]
To illustrate, the conversion n-joules of energy to n-joules of
accomplished work is impossible, since it would require a perfect
machine to accomplish. Perfect (100% efficient) machines don>t and
cannot exist.
[/quote]
This is beside the point. It does not address a difference between work
and energy. It is still my contention that is is confusing to say they
are something different without clear qualification. And I can think of
nothing clear about saying 'they are different'.
[quote]On another note, I did like your example of the energy stored by the
water trapped behind a dam. Still, I believe it is important to point
out that that this stored potential energy is entirely derived from
the energy flux supplied by the sun, and gravity acts in essence only
in the capacity of a "spring" to store this captured solar energy.
[/quote]
As far as the sun goes, it is not necessary to qualify how the water got
behind the dam. We are simply showing an example of energy. As far as
gravity goes, I predicated the example with, 'Keep it in simple terms',
and that is what I intended. I had already put on the table that energy
is ML^2/T^2 if a more rigorous examination were warranted.
[quote]
Harry C.
[/quote]
Best, Dan.
--
http://lakeweb.net
http://ReserveAnalyst.com
dbAtLakewebDotCom |
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