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[joppa]

Do you mind if I inquire as to your physical age, Michael? Just curious.

[Michael]

Hi Jonathan,

I don't think it is a question of semantics. That's why I think you need to rephrase your question. It would be semantics if two people were regarding some activity and one said, that is work, and the other said, no it is energy. What you are stating though is energy is not work, and visa versa. Energy is some kind of stuff. To clarify my point let's take a look at Jim's post.

>Electricity is energy. It can be consumed by an electric motor to do work.

A hurricane has energy. It can flatten a house which is work.

Wood is an energy source. It can be burned in a steam engine to produce work.

Gasoline has stored chemical energy. Used in an automobile it produces work.

Water on a mountain has energy. As if flows through a turbine it does work.

Anything that CAN produce heat or movement contains energy.
When it DOES produces heat or movement it does work.


The energy of electricity is also work. The subatomic movements we call energy are work.

The energy of a hurricane is also work.

>Wood is an energy source. It can be burned in a steam engine to produce work.
Means the same thing.

>Gasoline has stored chemical energy. Used in an automobile it produces work.
Same thing. Can also be called potential work.

Water flowing from a mountain is also work.

It is the same thing everytime. You need to define what this stuff energy is to prove otherwise.


Mike

_________________
meChANical Man.
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"All things move according to the whims of the great magnet"; Hunter S. Thompson.

[ovyyus]

Hi Michael,

[Jonathan]

>You need to define what this stuff energy is to prove otherwise.
That is not the only thing, you could also prove that the only other alternatives are wrong.
I think we can all agree that energy is or isn't work, that there is no half way.
So one could prove what energy is (I don't know) or prove that energy can't be work, and that would resolve it. I think I've done the latter, but to make it very clear, one can put it in a vaguely mathematical form:
E#c*W
W#d*E
where E is energy, W is work, d is dissipation, # is an attempt at writing "triple bar", and * is either "to do" or "of". These are the classic definitions found in textbooks. My original point in the other thread was that because of the equality of W and d*E, they are interchangeable. This means that in the definition of E, we should be able to substitute d*E for W, which gives E#c*d*E. In English it says that energy is the capacity to dissipate itself. Not only is this clearly a self-referential "definition", but it is also clearly untrue. It is like saying that a dog is the capacity to bark. It is true that dogs have that capacity, but they are more than just a capacity.
We got onto the secondary point of what energy is with respect to work because Michael said that energy and work are the same things. If this is true, then we have a new rule:
E#W
But using the same interchangeability as before, this also says c*W#d*E (since E#c*W and W#d*E). And doing it once more gives c*d*E#d*E (here W#d*E is used again). But here now we have nonsense, the capacity for action cannot be the same thing as the action itself (the action being the dissipation of energy), so our starting assumption that E#W must be false.
EDIT
Ovyyus, though I agree, I have to say that your analogy is a little off. The mouse trap with stored energy will weigh more, not that it'd be detectable. You could also (carefully!) send sound through each spring (one under tension and one not) and note the difference in the speed of the sound (that would be hard too). But I completely agree with the overall idea, that potential energy is timeless as long as it doesn't change. The only things that require time are things that have change as a part of their definition, like velocity or kinetic energy.
EDIT2
Technically, I proved that E#W is inconsistent with E#c*W and W#d*E, and the later two are circular to each other. But I'm quite confident that the first two are false. (I do believe E=W though).

_________________
Disclaimer: I reserve the right not to know what I'm talking about and not to mention this possibility in my posts. This disclaimer also applies to sentences I claim are quotes from anybody, including me.

[ovyyus]

Hi Jonathan,

[Jonathan]

I could be confused, but I think relativity says increasing the mass or energy in a region increases the spacetime curvature.

[ovyyus]

Hi Jonathan,

You mean relativity theory. Hmm, don't know about that.

You seem to be implying that space/time curvature can be effected by the presence of energy. If you are right then, by definition, an energy potential can not exist outside of time.

[Jonathan]

Still if I'm not confused, relativity theory says that the warping of space effects the way things move and the warping of time effects the way things change. Potential energy needn't change and the object that owns it needn't move, in order for potential energy to exist, so energy that is effecting spacetime needn't result in spacetime effecting the energy.

[Michael]

> How can you tell the difference between two exact same mousetraps where one is 'set' (spring under tension) and the other is not (spring or wire with no tension)? Both mousetrap springs weight the same, they both have the same temperature, they both look the same, etc. Yet one has the 'capacity to do work' while the other doesn't. How could you tell the difference between the two without resorting to a work (time) related measurement?

You can't that's my point Bill. The capacity for work, or potential for work, entails it can work (eventually). To due so means a movement against resistence over time. If you take time out of it, or space, the potential to do work is also gone. It is no longer work.

Jonathan, you say you've proved it, but you've proved nothing. I still don't know why you are arguing something that is already defined and well known by physicists. Let me try this again.

The definition of energy is the capacity to do work. This is because (as I mentioned before) energy is often shorthanded for potential energy, and kinetic energy. Potential, as in the potential for energy, or the potential for work. Kinetic as in movement, or work itself. If you take kinetic away from the definition completely, potential fallls apart because there in fact could never BE a potential. There is a slight difference to all of this though, I'll admit that. The definition of work would be force, applied against resistence, over time. Energy, which is a word definition of a measurement of either the potential for work, or work itself, is done by knowing the amount of resistence, and how much resistence will be moved, changed, etc. over what period of time. That will let you know how much force is present, doing the work. You could also know in advance how much force is there, and then be able to calculate how much resistence can be set upon, over what period of time. So you see how closely related it all is. This is a lot different than saying energy is some unknown stuff. Which is what you are saying. It's not.

Regards,

Michael

[Michael]

>In English it says that energy is the capacity to dissipate itself. Not only is this clearly a self-referential "definition", but it is also clearly untrue.

It is actually very true. If you understood the conservation of energy, and how all of this ties itself together you would get it.

Regards,

Michael

[Jonathan]

I would agree that energy has the capacity to be dissipated, but it cannot be defined as its own dissipation. Definitions cannot be self-referential.

[Jonathan]

I think I've got something even more conclusive. There is a conservation of energy law, but there is no conservation of work law. If you have a closed system, and things are 100% efficient so all energy is retrievable, and there is 1J in the system, then you can use that single joule to do any arbitrary number of joules of work. If you have 1J, and you do 1J of work, how much energy do you have left? 1J, it's just in a different (and in the real world mostly unusable) form.

[Grimer]

I think the whole of mechanics can be subsumed under Iterative Hierarchical Strain.

[erick]

Energy is by definition the potential to do work. Work in it of itself is simply the transfer of energy from one object to another. We perceive this transfer as work.

[erick]