# The Naked Scientists Forum

### Author Topic: Potential 'energy', but, on a ledge? Will it add mass?  (Read 7113 times)

#### yor_on

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##### Potential 'energy', but, on a ledge? Will it add mass?
« on: 10/03/2012 17:35:51 »
So I wrote this, somewhere.

"The relation you discuss is the one relative earths gravitational field but assume a meteor hitting it on the ledge. As it hasn't developed the relation relative the ground, more than 'potentially', it will not express this added gravitational 'energy' when interacting with that meteor, as I think of it at least :)

The 'potential' stuff is just that, 'potential'. And it's the relation and final interaction that will define the outcome. So you could say that this 'potential energy' is 'spread out' in space, potentially there, but only as a result of and in a interaction.

The spring though has been compressed, which is an interaction, and a outcome. There's nothing 'potential' about that compressed spring.
==

You can also think of it in form of the conservation laws. You impart a 'force' by compressing it, and using some 'lock' you force it to keep the 'energy' that compression brought with it. If you kick something so that it start to move, as that ball, the 'energy' it gets by your kick will 'bleed off' in time expressed as friction etc. But the spring can't bleed it off, although it should sooner or later rust, or otherwise decompose, :) and so disappear as a spring."

Got this as an alternative..

"The essential point is that energy has mass. The discovery of the equivalence of energy and mass was a fundamental one – and, despite its importance, it’s anything but obvious. As far as we know, that's just the way nature is built.

Adding energy to something (whether by kicking it to make it move, heating it, or raising it up and putting it on a shelf) therefore adds mass to it. Basically, every single constituent part of the object is now a bit heavier. "

Hmm

Which one is correct? My self I see 'potential energy'  as a relation basically, only satisfied in its final outcome. Against it we have the idea that elevating something in a gravitational field will add a rest mass to the object, in this case a ball resting on a ledge?

Thinking of it in form of conservation of energy the later seems possible, but thinking of it like I do, there should be no new rest mass added to that ball. Anyone that knows a experiment defining one or the other. It should be possible to define one as I see it, but I can't seem to find it?
=

( Me spelling sux :)
« Last Edit: 10/03/2012 17:53:31 by yor_on »

#### MikeS

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##### Re: Potential 'energy', but, on a ledge? Will it add mass?
« Reply #1 on: 12/03/2012 07:13:30 »
So I wrote this, somewhere.

"The relation you discuss is the one relative earths gravitational field but assume a meteor hitting it on the ledge. As it hasn't developed the relation relative the ground, more than 'potentially', it will not express this added gravitational 'energy' when interacting with that meteor, as I think of it at least :)

The 'potential' stuff is just that, 'potential'. And it's the relation and final interaction that will define the outcome. So you could say that this 'potential energy' is 'spread out' in space, potentially there, but only as a result of and in a interaction.

The spring though has been compressed, which is an interaction, and a outcome. There's nothing 'potential' about that compressed spring.
==

You can also think of it in form of the conservation laws. You impart a 'force' by compressing it, and using some 'lock' you force it to keep the 'energy' that compression brought with it. If you kick something so that it start to move, as that ball, the 'energy' it gets by your kick will 'bleed off' in time expressed as friction etc. But the spring can't bleed it off, although it should sooner or later rust, or otherwise decompose, :) and so disappear as a spring."

Got this as an alternative..

"The essential point is that energy has mass. The discovery of the equivalence of energy and mass was a fundamental one – and, despite its importance, it’s anything but obvious. As far as we know, that's just the way nature is built.

Adding energy to something (whether by kicking it to make it move, heating it, or raising it up and putting it on a shelf) therefore adds mass to it. Basically, every single constituent part of the object is now a bit heavier. "

Hmm

Which one is correct? My self I see 'potential energy'  as a relation basically, only satisfied in its final outcome. Against it we have the idea that elevating something in a gravitational field will add a rest mass to the object, in this case a ball resting on a ledge?

Thinking of it in form of conservation of energy the later seems possible, but thinking of it like I do, there should be no new rest mass added to that ball. Anyone that knows a experiment defining one or the other. It should be possible to define one as I see it, but I can't seem to find it?
=

( Me spelling sux :)
It takes kinetic energy to raise the ball.  When the ball is on the ledge that kinetic energy is now stored as 'gravitational potential energy'.  The ball because of it's height now 'weighs' less.  Does it's new weight plus the energy required to lift it equal its starting weight if looked at from the energy/mass equivalence point of view?

The meteor had kinetic energy when it hit the ledge.  Much of this kinetic energy will dissipate as sound and heat, ultimately heat.  What's left of the meteor on the ledge will still have a certain amount of 'gravitational potential energy.  If it were to fall of the ledge then more of the GPE will be converted to 'kinetic energy' but there will still be some left.  After all the meteor might yet fall down a hole.  It's perhaps more correct to think of the meteor in space as possessing kinetic energy rather than GPE as it's kinetic energy is likely to far exceed it's GPE.  Also, GPE is a restoring force and is more correctly used to describe the energy stored in a stationary object, much like the energy stored in a compressed spring.

Perhaps I have misinterpreted what you are saying but it seems to me that you maybe confusing GPE with kinetic energy?

#### Soul Surfer

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##### Re: Potential 'energy', but, on a ledge? Will it add mass?
« Reply #2 on: 12/03/2012 08:40:54 »
Gravitational attraction causes everything in the universe to try to collapse towards a mathematical singularity unless some opposing force is strong enough to prevent this happening for the moment allowing that body to possess some gravitational potential energy.

in the case of the stone on the ledge (wherever it has come from) this force is a combination of two main effects.

Firstly the electrostatic repulsion of the electron clouds around the nuclei of the atoms that make up the ledge.

Secondly the electrostatic attraction of the detailed shapes of the electron clouds that form the chemical bonds that hold the atoms together to form a solid.  As stresses increase it is these that are weaker and break first.
« Last Edit: 12/03/2012 08:42:53 by Soul Surfer »

#### yor_on

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##### Re: Potential 'energy', but, on a ledge? Will it add mass?
« Reply #3 on: 12/03/2012 17:49:52 »
Well, I lifted the citations out of a context so it may be ambiguous. But the question is simple.

If you lift/throw a ball 1000 meters up and leave it on a ledge, will its invariant 'rest' mass increase, or not?
I say no.

But it is interesting.
« Last Edit: 12/03/2012 17:51:30 by yor_on »

#### MikeS

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##### Re: Potential 'energy', but, on a ledge? Will it add mass?
« Reply #4 on: 12/03/2012 19:59:27 »
Well, I lifted the citations out of a context so it may be ambiguous. But the question is simple.

If you lift/throw a ball 1000 meters up and leave it on a ledge, will its invariant 'rest' mass increase, or not?
I say no.

But it is interesting.
I would say not.  The kinetic energy of throwing it onto the ledge has essentially been converted into GPE but it's rest mass remains the same.

#### yor_on

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##### Re: Potential 'energy', but, on a ledge? Will it add mass?
« Reply #5 on: 12/03/2012 20:23:40 »
And where did the Gravitational Potential Energy go?

#### MikeS

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##### Re: Potential 'energy', but, on a ledge? Will it add mass?
« Reply #6 on: 12/03/2012 20:48:41 »
And where did the Gravitational Potential Energy go?

It's a restoring force like storing energy in a spring.  The ball stores it's GPE by virtue of it's position in the gravitational gradient.  If it rolls off the ledge then it's GPE is converted into kinetic energy which is liberated upon contact with the ground as heat and sound and entropy increases.
« Last Edit: 12/03/2012 20:50:54 by MikeS »

#### yor_on

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##### Re: Potential 'energy', but, on a ledge? Will it add mass?
« Reply #7 on: 12/03/2012 21:55:55 »
Hmm :)

And the spring would be?
Come on Mike, we're here to argue :)

#### MikeS

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##### Re: Potential 'energy', but, on a ledge? Will it add mass?
« Reply #8 on: 12/03/2012 22:25:25 »
"The ball stores it's GPE by virtue of it's position in the gravitational gradient."

In this case it's a tensile spring by analogy.  It represents the gravitational attraction of the ball to the Earth.  The spring is under tension as the ball is held in place by the ledge.

I prefer the term debate. :)

#### yor_on

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##### Re: Potential 'energy', but, on a ledge? Will it add mass?
« Reply #9 on: 14/03/2012 04:10:15 »
Slightly more civilized sound to it, a debate I mean? And you are absolutely correct, we are gentlemen, as well as women, here on TNT,.

eh, TNS..

Still, that spring is really spread around in the earth/ledge system, isn't it?

#### MikeS

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##### Re: Potential 'energy', but, on a ledge? Will it add mass?
« Reply #10 on: 15/03/2012 20:07:09 »
Slightly more civilized sound to it, a debate I mean? And you are absolutely correct, we are gentlemen, as well as women, here on TNT,.

eh, TNS..

Still, that spring is really spread around in the earth/ledge system, isn't it?

The spring is obviously gravity but do you know why gravity is attractive and can you explain it in simple terms?

#### yor_on

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##### Re: Potential 'energy', but, on a ledge? Will it add mass?
« Reply #11 on: 16/03/2012 19:08:51 »
well, we've got a new member with some really interesting ideas :).

A lot of them somehow fitting how I see it, some of them taking me a far bit from from my own.
But I like that, we're not experimenters here.

We're all exploring what we think 'reality is'.
And to do that we need to think freely, and be wrong too at times.
Without anyone screaming :)

Somehow we can't all work in a patent office.
But we can all think, and we're feeling good doing it :)

Maybe that one is the most important?
to enjoy thinking.
==

As for my view of 'gravity' Mike? To me it's geometrical, it's how SpaceTime displace itself relative the observer.
To do it we need a local arrow. Or a arrow 'common for all'.
But I prefer the local variant myself.

So the ball on the ledge will always be defined locally, by the observer. and the 'potential energy' will be his definition of 'space and time' in his observation of a 'system'. The 'system' as such is a conceptual definition of where he thinks the 'cut offs' are applicable. And that's as close as I can come 'reality' for now.

#### MikeS

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##### Re: Potential 'energy', but, on a ledge? Will it add mass?
« Reply #12 on: 17/03/2012 06:45:30 »
yor_on

But that didn't answer my question
"do you know why gravity is attractive and can you explain it in simple terms?"

;)

#### yor_on

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##### Re: Potential 'energy', but, on a ledge? Will it add mass?
« Reply #13 on: 17/03/2012 07:18:31 »
Attractive becomes the wrong word if you see it as a geometry. Then it's a question of 'manifolds' possibly? To me 'gravity' is a geometry, and then it can't be a 'force' even if we define it such from other points of view.

What I might wonder about is how the 'geometry' can exist?
And there we have that word it all seem to fall back on :)

'Energy'

#### yor_on

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##### Re: Potential 'energy', but, on a ledge? Will it add mass?
« Reply #14 on: 17/03/2012 07:20:54 »
And if you think of that as a concept, then ask yourself what a 'gravitational time dilation' becomes :)

#### MikeS

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##### Re: Potential 'energy', but, on a ledge? Will it add mass?
« Reply #15 on: 17/03/2012 13:35:29 »
Attractive becomes the wrong word if you see it as a geometry. Then it's a question of 'manifolds' possibly? To me 'gravity' is a geometry, and then it can't be a 'force' even if we define it such from other points of view.

What I might wonder about is how the 'geometry' can exist?
And there we have that word it all seem to fall back on :)

'Energy'
Geometry it may well be but why does that attract objects to the Earth's surface?

#### CliffordK

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##### Re: Potential 'energy', but, on a ledge? Will it add mass?
« Reply #16 on: 17/03/2012 15:13:13 »
Of course, one doesn't always have to raise an object to be on a "shelf".
One can just take away everything else around it, and thus gain potential energy.

#### yor_on

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##### Re: Potential 'energy', but, on a ledge? Will it add mass?
« Reply #17 on: 17/03/2012 17:22:22 »
This one gives a nice analogue. Read it carefully and see what you think.
Einstein's geometric gravity.

#### MikeS

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##### Re: Potential 'energy', but, on a ledge? Will it add mass?
« Reply #18 on: 17/03/2012 18:40:39 »
This one gives a nice analogue. Read it carefully and see what you think.
Einstein's geometric gravity.

I have actually mentioned something very similar in a thread in this forum and that was without reading the mentioned article or anything similar.

The answer to why gravity is attractive is very simple and I have mentioned it before in various other threads.

GR tells us that gravity is warped space time.  Basically 'warp' means to distort.
So what is it that is being distorted.
Answer time or more correctly space-time but it is sufficient to just think of it as time.

Time is dilated (more warped) [relative to a distant observer] near to a large mass as compared to distant from that mass.
All  objects are travelling through space time.

An object with a large mass is travelling from dilated time to a less dilated time and it does that continuously. This is acceleration.
Gravity is acceleration.  Any object with significant mass is accelerating through time.
We keep out feet firmly planted upon the Earths surface because we are accelerating.  This is exactly the same as we would feel acceleration if accelerating at 1 G in a rocket.

I don't think I am intentionally expressing anything new here.  I am trying to explain what GR is telling us about gravity but most people don't seem to understand.  Gravity is acceleration.  Acceleration through time.  That is, a continuously changing (contracting) flow of time

Acceleration is an increase in distance covered per unit time.  That is the normal way acceleration is expressed but it is equally valid to consider acceleration as occurring through time continuously contracting (opposite of dilating).

Crystal clear?

This is not a new theory but I believe it is what GR is telling us but most people don't seem to see the wood for the trees.  It's very simple.  Gravity is acceleration through time.  What we feel as gravity on the Earths surface is actually constant acceleration at one G.
« Last Edit: 17/03/2012 19:33:50 by MikeS »

#### yor_on

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##### Re: Potential 'energy', but, on a ledge? Will it add mass?
« Reply #19 on: 17/03/2012 19:40:57 »
First of all, did you really read it?

If you had you would have found that your hypothesis and Einsteins are two different things. Although you both seem to agree on that gravity is equivalent to an acceleration the rest of your ideas belongs in 'New theories', and you know that. And referring to GR to say that yours ideas and GR are the same is not cool.
==

Try this one too soap bubbles and GR When Einstein looked for that fifth dimension he hoped would join the 4 we can measure into one 'whole' equation/SpaceTime he probably thought in similar lines to this.
« Last Edit: 17/03/2012 20:03:04 by yor_on »

#### MikeS

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##### Re: Potential 'energy', but, on a ledge? Will it add mass?
« Reply #20 on: 18/03/2012 06:14:45 »
What I wrote all hinges on the truth of these two statements.
(The second being derived from the first.)

(1) "An object with a large mass is travelling from dilated time to a less dilated time and it does that continuously. This is acceleration."

That statement is drawn directly from GR in as much that all objects are continually travelling through space time and a massive object dilates time locally relative to a distant observer.
Do you deny that?

(2) "Acceleration is an increase in distance covered per unit time.  That is the normal way acceleration is expressed but it is equally valid to consider acceleration as occurring through time continuously contracting (opposite of dilating)."
Do you deny that?

What is it specifically that you think does not agree with GR and therefore constitutes a new theory?
« Last Edit: 18/03/2012 06:42:05 by MikeS »

#### yor_on

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##### Re: Potential 'energy', but, on a ledge? Will it add mass?
« Reply #21 on: 18/03/2012 21:31:51 »
Mike, read the links instead. You asked me what I saw as a 'geometry' right? And described it as a 'force'. Just read the links and you will see what Einstein meant. It's no 'force' in his thinking although you can see it that way too, depending on what equations you use, and what logic you trust. In QM you might call it 'the 'force' of the Higgs' possibly :)

But Einstein used a geometrical description.

#### MikeS

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##### Re: Potential 'energy', but, on a ledge? Will it add mass?
« Reply #22 on: 19/03/2012 05:56:49 »
Mike, read the links instead. You asked me what I saw as a 'geometry' right? And described it as a 'force'. Just read the links and you will see what Einstein meant. It's no 'force' in his thinking although you can see it that way too, depending on what equations you use, and what logic you trust. In QM you might call it 'the 'force' of the Higgs' possibly :)

But Einstein used a geometrical description.
"do you know why gravity is attractive and can you explain it in simple terms?"
and
"Geometry it may well be but why does that attract objects to the Earth's surface?"

You said in a previous post.
"Although you both seem to agree on that gravity is equivalent to an acceleration the rest of your ideas belongs in 'New theories', and you know that. And referring to GR to say that yours ideas and GR are the same is not cool."

What I actually said in essence was.
"An object with a large mass is travelling from dilated time to a less dilated time and it does that continuously. This is acceleration."

You seem to think that is a new theory.  I maintain it is the natural outcome of GR.

I asked you in my last post what it was about that statement you thought did not come from Relativity.

I direct answer would be really appreciated.
« Last Edit: 19/03/2012 05:58:48 by MikeS »

#### MikeS

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##### Re: Potential 'energy', but, on a ledge? Will it add mass?
« Reply #23 on: 19/03/2012 06:33:18 »
"An object with a large mass is travelling from dilated time to a less dilated time and it does that continuously. This is acceleration."

Let's take that statement apart to see where the various ideas it expresses came from.
1) An object with a large mass dilates 'local' time relative to a distant observer.
2)Therefore, time is more dilated closer to the object than further away, again as perceived by a distant observer.
3) All objects are travelling through space-time continuously.
Therefore
"An object with a large mass is travelling from dilated time to a less dilated time and it does that continuously."
That is in full accord with GR.

4) In physics, acceleration is the rate of change of velocity with time.
Time contracting (opposite of dilating) will accomplish the same thing.

5) Therefore an object in an environment where time is contracting is accelerating.
Any massive object creates it's own gravitationally warped space time in which it is continually accelerating as it is continuously travelling through space time from a 'place' where' time is passing slower to a place where time is passing faster (relative to a distant observer).

I honestly believe this to be in full accord with GR and the known laws of physics.
If you believe I am wrong please be specific in stating in what way I am wrong.  Generalizations are of no help.

#### imatfaal

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##### Re: Potential 'energy', but, on a ledge? Will it add mass?
« Reply #24 on: 19/03/2012 11:42:01 »
Mike - Yoron is correct.  This belongs in New Theories.  Please stop

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##### Re: Potential 'energy', but, on a ledge? Will it add mass?
« Reply #24 on: 19/03/2012 11:42:01 »