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Author Topic: How would you define Energy?  (Read 8770 times)

Offline simplified

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Re: How would you define Energy?
« Reply #25 on: 23/03/2012 02:32:32 »
I thought Energy was defined as the potential for work, therefore energy is little pink fluffy creatures that exist in another dimension and all they do in our dimension is work.  Prove me wrong, haha.....
Can you make work without meal?Can energy make work without feed of time?Identically. :P
 

Offline Airthumbs

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Re: How would you define Energy?
« Reply #26 on: 23/03/2012 20:26:05 »
Can you make work without meal?Can energy make work without feed of time?Identically. :P

I gonna go for YES :)  If space is time, and the big bang created it, then what did the work, to feed time, without a meal!?
 

Offline yor_on

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Re: How would you define Energy?
« Reply #27 on: 24/03/2012 13:30:22 »
The best definitions are those that rings in what it do, and also can describe the mechanism by which we see it happen. There I have no notion of little pink fluffy creatures?
 

Offline JP

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Re: How would you define Energy?
« Reply #28 on: 24/03/2012 15:07:21 »
There I have no notion of little pink fluffy creatures?


You mean these?  They're pretty lazy, so I don't think they do much work.
 

Offline Geezer

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Re: How would you define Energy?
« Reply #29 on: 25/03/2012 06:33:19 »
Of course, every family has its blue sheep.
 

 
 
 

Offline simplified

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Re: How would you define Energy?
« Reply #30 on: 26/03/2012 13:57:20 »
Can you make work without meal?Can energy make work without feed of time?Identically. :P

I gonna go for YES :)  If space is time, and the big bang created it, then what did the work, to feed time, without a meal!?
Space is not time.The collision of time star and energy star caused the big bang.
 

Offline Pmb

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Re: How would you define Energy?
« Reply #31 on: 26/03/2012 15:38:37 »
Can you make work without meal?Can energy make work without feed of time?Identically. :P

I gonna go for YES :)  If space is time, and the big bang created it, then what did the work, to feed time, without a meal!?
Space is not time.The collision of time star and energy star caused the big bang.
You're right regarding space and time. Laymen seem to confuse it more than any other concept in relativity. Mathematically they are treated on the same footing to a certain extent. But they are quite different concepts physically - So said Einstein.
« Last Edit: 27/03/2012 12:41:42 by Pmb »
 

Offline dkeizer05

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Re: How would you define Energy?
« Reply #32 on: 27/03/2012 02:25:15 »
I thought energy was just existence. :(!
 

Offline Nizzle

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Re: How would you define Energy?
« Reply #33 on: 27/03/2012 07:12:32 »
Energy is Nature's Currency, like Geezer already hinted at by comparing it to money.

And black holes are like governments and banks.
 

Offline Soul Surfer

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Re: How would you define Energy?
« Reply #34 on: 27/03/2012 08:37:31 »
Energy is more like money than you think because you can borrow it to do something but you have to pay it back within a precisely defined time.  The more you borrow the quicker you have to pay it back.  Planck's constant is what tells you how quickly you need to pay it back and the uncertainty principle is the results of this borrowing process.
 

Offline imatfaal

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Re: How would you define Energy?
« Reply #35 on: 27/03/2012 10:30:50 »
Surfer - I agree but I would say this borrowing process is the result of the uncertainty principle rather than the other way around.   The physical interpretation of the maths is open - but the maths is clear, if properties are presented in infinite matrix form (via fourier transforms) then the non-commutative nature of those matrices will require an uncertainty.
 

Offline Pmb

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Re: How would you define Energy?
« Reply #36 on: 27/03/2012 12:50:29 »
Energy is more like money than you think because you can borrow it to do something but you have to pay it back within a precisely defined time.  The more you borrow the quicker you have to pay it back.  Planck's constant is what tells you how quickly you need to pay it back and the uncertainty principle is the results of this borrowing process.
I disagree. If you think of energy simply as something that is merely conserved then you have to explain why momentum isn't energy. Also  that is not what Planck said about energy. That expresssion for time-energy does nor mean that time isn't always conserved. It's unfortunate that so many people think that it is. However David Griffiths teaches differently in his QM text. I wrote out his derivation here.

http://home.comcast.net/~peter.m.brown/qm/time_energy_hup.htm
 

Offline imatfaal

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Re: How would you define Energy?
« Reply #37 on: 27/03/2012 14:28:23 »
Energy is more like money than you think because you can borrow it to do something but you have to pay it back within a precisely defined time.  The more you borrow the quicker you have to pay it back.  Planck's constant is what tells you how quickly you need to pay it back and the uncertainty principle is the results of this borrowing process.
I disagree. If you think of energy simply as something that is merely conserved then you have to explain why momentum isn't energy. Also  that is not what Planck said about energy. That expresssion for time-energy does nor mean that time isn't always conserved. It's unfortunate that so many people think that it is. However David Griffiths teaches differently in his QM text. I wrote out his derivation here.

http://home.comcast.net/~peter.m.brown/qm/time_energy_hup.htm

Peter - nicely written out and explained.  Still not sure I agree (to be honest I don't understand yet) - and waiting to see what SoulSurfer say.   

One quick point - on your first equation, I am thinking that an i is needed on rhs, or have i got wrong end of stick.
 

Offline Pmb

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Re: How would you define Energy?
« Reply #38 on: 28/03/2012 12:34:51 »
One quick point - on your first equation, I am thinking that an i is needed on rhs, or have i got wrong end of stick.
I don't understand what you mean. Can you clarify. By the way, I never posted a derivation of Eq. (1) and I really should.

Best wishes,

Pete
 

Offline yor_on

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Re: How would you define Energy?
« Reply #39 on: 28/03/2012 12:50:28 »
It all depend on how you see it. If you want a arrow that is 'the exact same' there is only the local reference frames you can use. Then that 'locality' is what is proven to be the 'exact same'. Any experiment that moves its 'clock' to where the observed 'time rate' discrepancy first was noticed will find both 'clocks to sync again.

So, assuming we could super impose those 'clocks', which we in theory can as the best clocks are radiation we have a locally 'same' exact arrow, if we go by 'clocks'. And then the best clock will be the clock that defines the arrow, 'c'.
 

Offline Soul Surfer

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Re: How would you define Energy?
« Reply #40 on: 29/03/2012 08:40:17 »
I feel that you may be talking at cross purposes and seeing slightly different features because you are coming at the concept from different directions.

Remember the HUP is frequently expressed as a position-momentum relationship and/or a time-energy relationship.  The basic dimensions of Planck's constant are that of Action  (a term not much used nowadays)

Planck’s constant =  6.626068 x 10-34  metres   x  kilogram  x  metres/second
                                                                  distance  x    mass    x   velocity
                                               i.e. distance travelled and momentum

Planck’s constant =  6.626068 x 10-34  kilogram . (metres/second)2  .  Seconds
                                                                mass times velocity squared   x  time period
                                                                           Kinetic energy   x time

So you are looking at a multidimensional uncertainty that covers all relevant dimensions taken together.  Those are only two planes through a larger figure

I see it as a sort of "noise level" in the universe.

One of my fundamental questions that I tend to put up on blackboards in my thinking and working areas is the value and dimensions of Planck's constant followed by the word Why?


 

Offline yor_on

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Re: How would you define Energy?
« Reply #41 on: 01/04/2012 09:36:10 »
Yeah, constants is the big mystery here. Why do they exist, and what defines them?
 

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Re: How would you define Energy?
« Reply #41 on: 01/04/2012 09:36:10 »

 

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