Talk:Energy

Error in gravity formula.

The formila in Gravitational energy section should be: E = -G*m1*m2/r^2 92.247.247.23 (talk) 23:00, 16 May 2010 (UTC)

No, that is the formula for gravitational force. Integrating to get energy gives you a different dependence on r. Not surprisingly, energy is this force multiplied by r, a distance, so it comes out E = 2GmM/r. SBHarris 17:17, 18 May 2010 (UTC)

Edit request from 99.13.123.215, 20 May 2010

{{editsemiprotected}} My science teacher said that everything has energy. I didn't see that at all in the details of or about energy.

I was wondering if you could add that in there in big bold letters! 99.13.123.215 (talk) 00:31, 20 May 2010 (UTC)

It does actually begin by saying, In physics, energy is a quantity that can be assigned to every particle, object, and system of objects - this is the very first sentence in the article.

We don't write things in big, bold letters because we have to try and cover everything.

You might also try simple:Potential energy and Potential energy.  Chzz  ►  01:04, 20 May 2010 (UTC)

Edit request from 141.155.107.173, 8 June 2010

{{editsemiprotected}} The current page starts with: In physics, energy (from the Greek ἐνέργεια - energeia, "activity, operation", from ἐνεργός - energos, "active, working") is a quantity that can be assigned to every particle, object, and system of objects as a consequence of the state of that particle, object or system of objects.

I suggest the following change:

In physics, energy (from the Greek ἐνέργεια - energeia, "activity, operation", from ἐνεργός - energos, "active, working") is a scalar dimensional quantity that can be assigned to every particle, object, and system of objects as a consequence of the state of that particle, object or system of objects. Its dimension is M L²T ^-2.

141.155.107.173 (talk) 03:40, 8 June 2010 (UTC)

 Not done: That's useful information, but I think that adding it to the lede makes the article seem considerably less accessible to the lay reader. If the physicists reading this article agree that is an accurate change, it should go somewhere else in the article. Tim Pierce (talk) 12:12, 8 June 2010 (UTC)

It's in the lede, just at the end of the first paragraph rather than the start. This seems a better place for it to me. Algebraist 12:14, 8 June 2010 (UTC)

"scalar dimensional" would lose many readers immediately if that were in the first sentance. David Hollman (Talk) 10:44, 8 September 2010 (UTC)

rest energy expression

Under the subheading Kinetic Energy:

Regarding the last expression for kinetic energy E_k=mc²((1-(v/c)²)^-1-1)

For v=0 the given expression becomes E_k=0. But the next line after this equation is:

A mathematical by-product of this work (which is immediately seen in the last equation) is that even at rest a mass has the amount of energy equal to: E_rest = mc²

Though not incorrect readers will expect the expression for E_k to become E_k=mc² for v=0. Maybe an intermediate expression using a symbol for rest mass is needed.

--Phononcondensate (talk) 14:32, 1 July 2010 (UTC)

I've fixed it a bit. The reader needs to know that the two right hand side terms are total and rest energy, so that when the left hand side is zero (v = Ek = 0), the right hand side terms are equal, and thus total energy = rest energy = mc^2. SBHarris 18:47, 1 July 2010 (UTC)

Give a simplified (limited) definition of energy - rather than none

A number of physical concepts and quantities do not have "universally valid" or "generally agreed" definitions (possibly none at all), after they are analyzed to "the ultimate depth". However, this understanding comes only after a systematic and thourough study of the subject, which begun with some simplified, or limited, or particular definitions. Amateur opinions on impefection of definitions, which are not based on serious study and understanding of the problem, disregard the fact that these "imperfect" concepts have lead to great cognitive advances and technological developments in recent centuries. It therefore seems rather unreasonable to limit the article on energy to roundabout statements that it "is a quantity that can be assigned to every particle, object, and system of objects as a consequence of the state of that particle, object or system of objects. Different forms of energy include... etc". Even if the same could not be said about some other quantities, it hardly helps a lay person to get any clue on "what this energy thing is about". Therefore, I dare suggest that some simplified highschool definition should be inserted somewhere at the beginning of the article (such as "the ability of an object to do some work; it has so much energy as much work it can do"), preferably somewhat better worded. Of course, together with a note that this is not the "general" definition. And then you can proceede with other details and explanations. —Preceding unsigned comment added by 89.201.201.125 (talk) 00:58, 16 July 2010 (UTC) Levanat

I suggest that the first whack start by defining energy as a differential quantity which is conserved in isolated systems over time. That allows us to avoid having to define its absolute value in systems (since in conservation we are only interested in how the value changes, not what it IS). We can then name a few types of equivalent energy that can add or substract energy from systems, by their moving into and out of such systems (kinetic energy, heat, light, mass, etc). Then we can note that in classical mechanics and special relativity, the absolute value of energy in a closed and isolated system depends on our reference frame (event though this differing value is conserved in all frames), and also has several different definitions in various theories of relativity, all of them connected with some type of mass. We can note that in special relativity, in frames where a system has zero momentum, theoretically all of its energy can be converted to work, so long as we can satisfy the second law of thermodynamics. And finally that in some systems where space-time is expanding, energy is not conserved, unless certain types of gravitational potential are considered to represent negative energy. Is that the kind of thing you have in mind? SBHarris 01:58, 16 July 2010 (UTC)

This proposal looks more appealing than the present intro. Perhaps something like "a quantity that is conserved in isolated systems due to translational invariance of time" should be immeditelly followed by a reference to work (e.g. as a note on the pioneering role of kinetic energy) and a reference to mass, keeping all "chatty" simple at this first round (e.g. "particle physicists specify mass in energy units"), no links yet. To be honest, I do not quite feel up to writing a full specific proposal, and my main concern was that an average reader might give up before reading all fine points in the rest of the article if he could not find something "tangible" in the intro. As for physicists, if any visit this topic, they will molest you in the discussion page anyway. —Preceding unsigned comment added by 178.160.22.100 (talk) 01:57, 17 July 2010 (UTC) Levanat

Yes. The work should be there. Just saying it is a quantity of some sort or the theoretical aspects of the 'quantity' don't just cut it (for me) especially when it is something (almost) tangible. I did change it. Now it states that it is often understood as capasity to perform work (physics). I think that should convey the gist of it. Feel free to comment (or change). --Samoojas (talk) 16:41, 13 August 2010 (UTC)

I find this to be an appropriate improvement of the intro. It looks much more tangible now, and yet opened towards the rest of the article without unnecessary claims about formal definition.Ilevanat (talk) 02:01, 21 August 2010 (UTC)

I believe that the definition is not completely general. This definition states that "energy is the capacity to perfom work". Work is one the ways by which energy is transferred and, therefore, produces changes in the system receiving the energy through the work performed. If we are going to define it that way, we should include all the other ways to produce those changes (other ways to transfer energy). So it should read "the capacity to produce changes on other systems". Energy not only produces changes via work but also through heat and mass transfer. In the first two cases, there is no net transfer of matter. In the last case, matter is transferred and, therefore, all the forms of energy associated to an amount of matter are transferred with it. I am going to change the definition to extend it. It will be still simple but more general.George Rodney Maruri Game (talk) 22:37, 5 December 2010 (UTC)

Take care you don't confuse matter (poorly defined and not conserved) with mass (better defined and conserved, and basically equivalent to energy). Energy CAN be transferred into and out of systems without transferring matter (defined as fermions), but energy can never be transferred without transferring the MASS it is associated with (which is a property of BOTH fermions and bosons, at least in closed systems where space time is not expanding). Thermal energy and radiation are not matter, but both of them do have mass. "Work," like "heat" is defined only as some kind of energy in motion across a boundary. Both work and heat add "mass" to whatever they act on, according to how much heat is transferred, or work is done. SBHarris 02:47, 6 December 2010 (UTC)

What is the defenition of chemical energy? —Preceding unsigned comment added by 98.114.166.229 (talk) 21:16, 27 September 2010 (UTC)

Processes are generally categorized as energy conversion processes, whereby energy is changed from one container to another, (at a higher existence of entropy). And Chemical energy, like from an electrochemical battery cell, is energy that is derived from the internal energy of a chemical compound.WFPM (talk) 11:56, 20 October 2010 (UTC)

ENERGY, "ENERGY", energy, and "energy"

The problem with this page seems to be that it discusses an entity which is very abstract. ENERGY is the collection of phenomena under study, each form forever beyond the reach of our direct knowledge, while energy is but one of these phenomena. "ENERGY" is the sum of our models concerning um, maybeeee.....energy? While "energy" is the particular model under discussion in any singular way.
So, ENERGY cannot be defined, nor can energy, and "ENERGY" is too big to handle except in one of its specific instances, e.g., E=mc^2, I ran out of _energy_ for more examples...etc. So, therefore, Q.E.D., only "energy" can be defined fairly well. Link this page to these other uses, and stop trying to stretch the Sierpinski Carpet.

Or in other words, "HEY YOU KIDS! GET OFF MY LAWN!"

Now go wash your hands and have a cup of tea and a sit-down.

Thanks. --TheLastWordSword (talk) 22:09, 15 November 2010 (UTC)

If you use a single dimensional (S versus T) diagram to depict the physics of motion, But supplement it with a force vector, which sticks perpendicularly out of the paper to depict the magnitude of any force that causes a motion in the S-T diagram, Then you have a way of relating the force to the indicated motion in the indicated manner. An integration of the force vector during the applied time interval (Delta T)will give you the value of the impact that was applied to the impelled particle, and therefor, if you know its mass, you can calculate its change in momentum (M x delta V). Also if you integrate the force vector over the distance traveled (Delta S) by the particle during a time interval, you can calculate its change in kinetic energy of motion, which is M/2 times the integral of F squared. And since you soon note that to give additional energy to a moving particle you first have to catch up to it with your impelling force, it makes apparent the difficulty in causing a particle to achieve a velocity limit by sending out an impelling force.WFPM (talk) 13:20, 16 November 2010 (UTC)

Energy is described not defined.

Energy is described via its manifestations upoin matter. So what is enery? Bcuratolo (talk) 16:58, 24 January 2011 (UTC)

I agree, this is one of the worst opening paragraphs on wikipedia. [comment by 92.17.89.69]

Okay, a bold edit needed

Okay, agreeing with these many complaints and seeing not much done, I've been WP:BOLD and rewritten the LEDE to define energy as the ability to do work, which work exerts pushes and pulls through distances. It's also equivalent to mass, and never appears without mass. Potential energy appears as trapped energy, when pushes and pulls through forces are made, and the new configuration is locked so it cannot relax (like a spring). Heat is resolved to EM or kinetic energy, and thermal energy to kinetic and potential. The last part of the lede in which entropy, which conservation, conversion, and so on are discussed, is not changed as much. I've pointed out that if you transfer energy to another sytem by any means than just adding some matter to it, you're going to change it, because you've done work on it. SBHarris 01:04, 10 February 2011 (UTC)

Lots of weirdness

Energy, momentum, potential energy, speed, relative mass etc are all definitions created in their relation. When you use them you 'lend from time', that is define a coming 'moment in time' as a possible interaction, and then define whatever property you use from looking at that possible interaction. You have invariant mass defined as invariant in all frames and motions, not relativistic as that is a definition of a relative mass (relation), and that goes for momentum too as far as I know. If you don't get the basics right you will stare yourself blind at equations made from flawed premises. It's strange, you guys should really know this? Do you have any General relativity in your courses, or is it all 'quanta'?

What goes for momenta "as far as you know"? There is no "invariant momenta". The invariant quantity is the E,p,p,p 4-vector that includes energy. And the length of which is invariant mass. But this is not an article about mass, or rest energy. It's an article about energy so we are stuck dealing with the fact that it is conserved but relative to the observer. SBHarris 18:53, 9 March 2011 (UTC)

==

Momentum in a photon is a relation to a invariant speed 'c', from any frame measured, expressed differently from any of those frames as 'energy', when measured from whatever frame, depending on its speed relative that 'photon/wave'. And so it is 'relative'. Seen as a 'lightquanta' we express it differently. But a photon have no 'rest frame' as I know? Am I wrong there?

No. you're correct. The momentum a single photon is anything you like (down to something approaching zero, or large wihtout bound), since your observer of the photon can be in any frame you like. All of them see the photon moving at c, but each sees a different photon E and p. Kinetic energy for massive objects (the photon has no mass = rest mass) is the same, in a way. For any single particle kinetic energy can be anything you like, down to zero (rest frame of the moving object). Rest energy = rest mass is the minumum energy for massive objects. For systems of particles where we cannot find a frame where the KE of every particle is zero, the minimum total energy is in the center of momentum (COM) frame where system p is zero. Im that frame, the residual kinetic energy of the system contributes to its invariant mass (as do the various rest energies and potentials). See systems section in kinetic energy. That is sort of the "rest frame" of the system, even though parts of it are moving. Systems of photons also have an invariant mass, which is their mass in their COM frame (which doesn't change in a particle annihillation that makes photons, for example, so invariant mass is conserved).

=

"For systems of particles where we cannot find a frame where the KE of every particle is zero, the minimum total energy is in the center of momentum (COM) frame where system p is zero. Im that frame, the residual kinetic energy of the system contributes to its invariant mass (as do the various rest energies and potentials). See systems section in kinetic energy."

Thanks for your answer SB :) and, I have no problems with your statement, that energy is measurable after all. That is, you are referring to the system 'jiggling', as I read it? And that's also my point :) 'Energy' needs to be able to be measured if you want to refer it as belonging to a single object. And there we have 'jiggling' and compression as the telltales I know off. Compression as the spring still have a added 'invariant mass' even after the dissipating kinetic energy, produced in the compression, is gone.

==

"Potential energy appears as trapped energy, when pushes and pulls through forces are made." is terribly wrong. Where the he* do you get the idea that 'potential energy' pushes and pulls?

That's not what the sentence says. It says "potential energy appears as trapped energy, when pushes and pulls through forces are made." Which it does. There may be other ways to store potential energy besides letting a force act through a distance where the energy doesn't go into some other form of energy like kinetic E, but this method is the most common one. How do you make potential energy except by doing work? SBHarris 18:53, 9 March 2011 (UTC)

==

'Trapped energy' Can you prove that experimentally? Except in a compression? Are you thinking of 'relative mass' too? I'm sorry, maybe I'm not getting your idea right? Energy is interactions to me, or as expressed in a compression. Can you show me any proof for a speeding spaceship for example, storing 'energy' in its relative motion? If you mean the 'stress energy tensor', the warping of SpaceTime by 'relative speed' I might agree, although I have trouble defining its speed even so, maybe SpaceTime hasn't though? But as far as I know there is no 'energy' stored in that Spaceship I mentioned here? It makes me head hurt assuming that we have all kinds of 'secret, invisible, and unmeasurable, energy stored in that Spaceship :) Or? Can you prove my assumption wrong? If so I'm very interested. You just need to link me to the experiment proving it.

You can see energy stored when mass changes. In fusion, you bring two charged nuclei together and they are compressed against their EM fields like springs, until they reach a point that the nuclear force draws them in where they bind. That is a process that stores energy, if you are a supernova making (say) atoms of uranium. Each uranium nucleus now sits like a coiled spring, with more mass than the nuclei it was made from, and the extra is the mass that you trapped when you did the work on it (the temperature and kinetic energy did the work, and was trapped). When the uranium is split later, the opposite process happens. All these energies are stored as nuclear and EM potential energies, which trade off (move of one is made than the other is destroyed). Experimentally, this stuff is called nuclear fission and fusion. Potentials in both (fields which have mass) are converted to kinetic energies and EM radiation. There is nothing special about your coiled spring-- it's just another system that has stored potential. It's like a book that you picked up and put on a table. You store energy in that system. When the book falls, it's converted to kinetic energy, then heat (which is purely kinetic energy in monatomic gases, but half EM potential energy and half kinetic energy in solids). SBHarris 21:28, 10 March 2011 (UTC)

The Book is a interesting example. I can see some of your thoughts on the subject there but as far as I know there is no measurable new energy stored in that book, although there is different views on it :) simply expressed I would formulate it as 'gravity' is no force, therefore you won't get any extra energy stored in the book, that it will interact differently when falling is not a result of its 'intrinsic energy' being changed, to me it's a result of a different position in SpaceTime relative the object it may interact with, and that I see as a result of 'distortion/potential gravity/stress energy tensor'. As for why I call the spring the only example I know of? Well, it's not true, as it to me is the exact same principle as the one making a Black Hole, compression but there's my reason for accepting it. "You can see energy stored when mass changes. In fusion, you bring two charged nuclei together and they are compressed against their EM fields like springs, until they reach a point that the nuclear force draws them in where they bind. That is a process that stores energy." That one I will need to think off, I'm not sure. But I enjoy your views and I will get back to you when I sorted my thoughts out. What I can say though is that as long as we're discussing 'energy' as a concept I have no problem with adding different 'energies' interacting into a greater amount of 'stored energy', as long as we are discussing the same principle that, in time :), fill up a Black hole with more 'energy', coming from the infalling 'debris' well, sort off :)

A pleasure reading you. Yoron.

==

To make my point clearer, consider that spaceship crashing at three possible locations simultaneously, ala Feynman 'paths' :), delivering you three different 'energies' in those interactions. So, which one had it 'stored'? That one isn't that clear though as you can define it as a relation relative those objects, although when in a uniform motion you are free to define all motion to only one of those objects and if we have three (same exact invariant mass) uniformly moving at different speeds relative you, giving you three different energies? Still, better to consider how you define that 'stored energy' right :) You do it through using your inertial frame, don't you? Like Earth. So when you speak of that stored energy you mean 'relative Earth as a 'inertial frame' '. Or do you know any other way? And as all uniform speeds are the same in a black box, so your definition becomes not only relative, but also indefinite as I see it.

Here you are talking about kinetic energies, which are not stored in single objects (for reasons discussed above) but are stored in a dispersed and non-locatable way, in SYSTEMS of objects (and such minimal kinetic energies, easily seen in the system COM frame, are invariant). Potential energies don't involve motion, and because of that, they store energy in a way that is invariant from the beginning, but that's natural because they always involve doing work against some field/force, so a system of two objects (at minimum) is always involved anyway. Compress a spring and its increased mass is the same in all frames, since the mass increase shows up in the COM frame, and is invariant mass. However, like the book on the table, there's no motion storing the energy. The field and configuration of objects does it. Pull two objects appart gravitationally and that system stores the energy without storing it kinetically. This storage is also invariant and is seen by all observers, even though you cannot locate it precisely in space. Gravitational waves are one more interesting system where the energy is stored as a potential, but not in any location smaller than the wavelength of the wave. You have to "stand back" and look at the thing from a distance to "see" the effect of the energy (which is that the wave carries off energy and mass from systems, just must contain energy in itself somewhere, albeit diffusely). SBHarris 21:28, 10 March 2011 (UTC)

Yes I agree, by defining a arbitrarily chosen 'system' you can define a 'potential energy', or just 'energy', as a relation existing between the objects in that 'system'. What I don't like is when it sounds as if this 'energy' actually 'exists'. It doesn't, not until the interaction. I differ between measurable 'energy' (compressed spring) and conceptual 'energy' as in a 'system' where you want to light up the possible interactions and relations existing. Gravitational waves is to me 'vibrations' in the 'Jello field of gravity/SpaceTime', not 'energy' per se and the reason is that there is no 'force' involved. To me SpaceTime is somewhat like a Jello :) You can send 'chock waves' through it that 'distorts' it, propagating, but there is no 'energy' involved, that is when you're inside the distortion I don't expect you to weight/invariant mass more (as long as we're not talking a compression). Still, I see why it's seen as a very useful concept when manipulating mathematics, and I better add that I didn't react on your article as such, just on some comments I found unclear in the talk session. But, to me a added 'energy' should also be measurable, as 'jiggling' or as an added invariant mass (greater gravitational potential). I'm afraid this talk page may grow :)

==

Entropy is very simple to understand if you look at it as 'energy'. Not that we can lift up a ounce of 'energy' but it is a very useful concept. Then entropy will be that 'energy' interacting and so doing lose some of its 'energy' falling into a lower state. That why you will find our universe to equalize out in the end, all energy states being at that level where none can be used anymore, also called 'work done'. Why we don't do that spontaneously is because you need to add some 'energy' to any system you want to start interacting losing 'energy'. And that saves us all from instantly decaying. If you want to understand your equations you need to look behind them, to the concepts they manipulate. In chemistry entropy is expressed as heat, but the real state that change is 'energy', even though not defined by itself. Maybe you could use the word radiation instead of heat, I don't know, but 'energy' is the proper one for it I think as even radiation has a end state, as in a photon interacting annihilating itself.

"Energy is described via its manifestations upoin matter" If you by that mean relations interacting, losing energy by it and falling into lower energy states, as seen for the whole system? But there are no manifestations, only transformations. Some of them may end in a higher energy for part of those relations but always losing energy as a whole 'system'. The only thing 'defining' energy that I know of is the compression of a spring. After the kinetic energy has 'clung out' there will still be an added 'invariant mass' to that compressed spring as compared to it before getting compressed. And that's the only proof I know for the idea of 'energy'. But it's perfectly sufficient too :)

If you look at the stress energy tensor you will see that it uses property's only defined in a relation, like momentum. The energy that transforms into 'oblivion/SpaceTime' is expected to add to that tensor as I see it. And why it has to do so is because all interactions not only transforms, but also loses some of that 'energy'. As we have a definition of 'conservation of energy' we still need it to stay trapped. So it has to add to 'SpaceTime', and then the stress energy tensor is what you have left, as I know that is. The universe is weird :)

Yoron. User:178.30.6.228 12:52, 9 March 2011 (UTC)

Break

Look, nobody has time to go into this with you. Read the article carefully first. The stress-energy tensor only talks about energy-momentum flow through a point, and if you want energy in a volume you need to integrate around the volume of the thing. That's why some energies can't be expressed as dE/dV quantities-- you have to define your volume, integrate around it, and then step away and look at it from flat space. The energy that volume contains is then its invariant mass and the thing that generates that volume's gravitational field. There's your energy.

Gravitational waves are like shock waves (especially shear waves in a solid) but they carry away energy just as shock wave does. They do work (force x distance) on the emitter, and on the receiver. They exert forces on the emitter and the receiver. Example: read the article on the Hulse-Taylor binary system, which is a system of two neutron stars, one of which is a pulsar. This system orbits with a period of only 7.75 hours, coming as close to each other as twice the distance from Earth to moon. The power of the gravitation radiation from this is calculatable in general relativity and is 7.35 trillion trillion watts (10^24 watts). That's almost 2% of the energy that our Sun puts out as light, only this is coming out as gravitational waves. It exerts a force on the system and causes the stars to in-spiral as they lose energy and angular momentum-- they might as well be swimming in some viscous fluid. That's real work, a real force, and a real effect, which has been measured because the rotating pulsar is so great as a clock. Because it's polarized gravitational wave radiation, it carries away the angular momentum from the system, like a polarized light beam would do, but not like any nonpolarized EM radiation from any star (like ours) would do. It only has one possible explanation, and it fits Einstein's prediction over 30 years to within 0.2%. It won a Nobel Prize in 1993 for the guys who discovered and analyzed it (that's from your country, Sweden).

So-- the book raised to the table only increases the potential of the system, but its mass wouldn't change if the force and distance to put it there didn't come from somewhere else in the system (like my muscles, or you could do it with a coiled spring). The mass and gravity field of the whole Earth wouldn't change if you just moved energy from here to there like that, but if you believe energy left the coiled spring, you must believe it went into the system of book+Earth. Just WHERE, you can't say, but from far away, it's still there, even though not in the spring. So where else would it be? In the gravitational potential.

Finally, remember where those atoms heavier than iron and nickel come from. It takes energy to make them and fusion to larger atoms is losing propositon that saps and stores energy, not creates it. So where does this energy come from. It turns out that it's mostly gravitational energy from the collapse of a supernova, so that's stored gravtiational potential also-- except this time in heavy atoms. On a larger scale you can see that a planet like Jupiter still radiates more energy than it gets from the Sun. It's obviously still slowly colapsing, and that potential energy is converted to infrared.

and would you please sign your posts with four tildes: ~~~~. Or pick a username like Yoron? SBHarris 07:56, 12 March 2011 (UTC)

Hm.

Okay, maybe you feel that I'm attacking your article? if so, nope, as for signing every comment, you filled in my original writing with yours, I answered them, staying inside the caption I made originally? Anyway, you raise a question I'm not sure I can answer, with your statement that gravity is energy, as that seems to be the way you look at it? In a way I agree, maybe I don't see it clear enough? Or possibly gravity and its gravitational quadrupole moment are different. Einstein himself seemed to have changed views on gravity waves a couple of times :) so I think I'm excused if so. Gravity is definitely related to 'energy', but it's not a 'force'. If you state that energy contain gravity though, I have no problem agreeing. When it comes to the book I still say you will find no new energy in it. But we seem to agree there? When you define the energy as existing as a gravitational potential, I call it a 'stress energy tensor'. As for defining a arbitrarily chosen system, trusting this to 'define' the energy's boundaries? Then I don't agree, you can always widen this 'system' book-ground, to the whole universe if you like, and still find the same 'energy' released in the final interaction with the book hitting ground, with that 'energy' having been 'somewhere' inside your 'new system' too, as I see it?

But you've given me a lot to think of, and it still was a pleasure reading you. Yoron. 178.30.69.236 (talk) 23:07, 12 March 2011 (UTC)

Nuclear binding energy is converted

The table in this section looks like it has been vandalized.User:Bleeisme

I don't see where the problem is. Anyway, the place to make this comment is on the TALK page of nuclear binding energy. Please sign your comments with four tildes: (~~~~) SBHarris 21:47, 10 March 2011 (UTC)