Does force acting at a distance impart energy?

[finiter]

The existing view is that force acting at a distance can impart energy. But I propose an alternate view: the force does not impart energy, but causes thermodynamic changes (in the body) such as changing the speed and internal energy. An increase in speed causes a reduction in the internal energy and a decrease in speed causes an increase in the internal energy, thus the total energy remains constant. The changes in the internal energy can cause either heating or cooling. That is, unless energy is put into the body or removed from the body, a force on itself cannot impart or remove energy from the body.

[DrRocket]

The existing view is that force acting at a distance can impart energy. But I propose an alternate view: the force does not impart energy, but causes thermodynamic changes (in the body) such as changing the speed and internal energy. An increase in speed causes a reduction in the internal energy and a decrease in speed causes an increase in the internal energy, thus the total energy remains constant. The changes in the internal energy can cause either heating or cooling. That is, unless energy is put into the body or removed from the body, a force on itself cannot impart or remove energy from the body.

 

First it is not force acting at a distance that imparts energy. It is force acting over a distance.

 

Second it is a logical consequence of Newton's laws of motion that a force [math]F[/math] acting on a mass [math]m[/math] over a distance [math]d[/math] results in a velocity [math]v[/math] that satisfies

 

[math]F \times d = \frac {1}{2} mv^2[/math]

 

and [math] \frac {1}{2} mv^2[/math] is defined to be the kinetic energy of the body.

 

There is no notion of "internal energy" or indeed any internal structure in the particle picture of Newtonian mechanics.

 

So to accept your theory one must reject established mechanics or adopt a completely new definition of energy. You cannot "speculate" regarding a definition, and if you reject mechanics which is rather well supported by a mountain of empirical evidence, then whatever you are talking about is not physics. Passing to special relativity does not change the picture materially.

[spin-1/2-nuclei]

Hello Finter,

 

Internal energy does not change when temperature increases, this is because they are not directly proportional. Temperature is only proportional to the kinetic aspect of the internal energy.

 

This is why we have the concept of specific heat. A though experiment I'd like to propose to you, is to ask yourself why it takes more external energy to heat substance A than substance B. For example, would you say that a 1kg strip of metal would reach 100C faster than a 1kg sample of water? If yes, why? If no, why?

 

Cheers..

[finiter]

Hello Finter,

 

Internal energy does not change when temperature increases, this is because they are not directly proportional. Temperature is only proportional to the kinetic aspect of the internal energy.

 

This is why we have the concept of specific heat. A though experiment I'd like to propose to you, is to ask yourself why it takes more external energy to heat substance A than substance B. For example, would you say that a 1kg strip of metal would reach 100C faster than a 1kg sample of water? If yes, why? If no, why?

I read your comments in the classical physics forum. I agree with whatever you have stated in the last posting there. In fact, I am happy that you are here.

"Internal energy does not change proportionately when temperature increases". This was actually what I wanted to say. But in that forum, I just used questioning as a method to elucidate this point. So to make things clear, I will say that the internal energy is the sum of the kinetic part and the rest. In your thought experiment it requires more energy to heat water. Where does this energy go? Partly to increase the kinetic part and partly as the rest. In iron, also the same thing happens with a lesser amount of energy. So the specific heat part (say the kinetic part), in my opinion, represents heat energy and the rest simple internal energy. Now I think that we agree in our views. Or have I differed from you?

 

[spin-1/2-nuclei]

I read your comments in the classical physics forum. I agree with whatever you have stated in the last posting there. In fact, I am happy that you are here.

"Internal energy does not change proportionately when temperature increases". This was actually what I wanted to say. But in that forum, I just used questioning as a method to elucidate this point. So to make things clear, I will say that the internal energy is the sum of the kinetic part and the rest. In your thought experiment it requires more energy to heat water. Where does this energy go? Partly to increase the kinetic part and partly as the rest. In iron, also the same thing happens with a lesser amount of energy. So the specific heat part (say the kinetic part), in my opinion, represents heat energy and the rest simple internal energy. Now I think that we agree in our views. Or have I differed from you?

 

Hello Finter,

 

Yes, we have differing views, but only in the part that pertains to the specific heat. The specific heat and the kinetic energy are not related. If I may, I'd like to suggest another thought experiment.

 

So, since the temperature is the measure of the kinetic energy. Both the iron and the water are now at 100C, therefore they have the same kinetic energy, but do they have the same internal energy? The specific heat suggests that they cannot.

 

To say this in a more clear way.

 

The temperature of the water and the iron are now the same - so they are both at 100C, thus they have the same average molecular movement. What differs here is how long we had to hold them over the bunsen burner to get to that point.

 

So, if the temperatures are both the same, then we can say that the kinetic energies are the same, but if it takes longer to heat up A than it does to heat up B we can say that A has a different specific heat than B.

 

Thus,

First we must mathematically define the object's heat capacity

which we will say is..

 

heat capacity = the heat transfer (Q) / the change in temperature

 

which is just the mathematical way of saying heat capacity describes how fast something heats up.

 

The reason things require different amounts of energy to heat up can be attributed to the molecular and supramolecular structures, because interactions between atoms in molecular systems as well as the interactions between molecules in supramolecular systems will detract from the energy that can be directly used to increase the kinetic energy which must increase to increase the temperature.

 

Let's stop there for now, and check our bearings, and once we are on the same page we can move forward..

Cheers..

Edited August 23, 2011 by spin-1/2-nuclei

[pantheory]

The existing view is that force acting at a distance can impart energy. But I propose an alternate view: the force does not impart energy, but causes thermodynamic changes (in the body) such as changing the speed and internal energy. An increase in speed causes a reduction in the internal energy and a decrease in speed causes an increase in the internal energy, thus the total energy remains constant. The changes in the internal energy can cause either heating or cooling. That is, unless energy is put into the body or removed from the body, a force on itself cannot impart or remove energy from the body.

As Dr. Rocket explained, the primary definition of energy in physic is a force applied to an object over a distance which defines the increased energy that the object being acted upon, receives. The totally different concept of "a force at a distance" is simply a force and nothing more until an action takes place concerning an applied force. There have been a number of arguments in physics concerning the validity of pulling forces at a distance such as gravity and magnetism, etc. But this is an entirely different subject. You can always argue about theoretical mechanics but not definitions. You can say I don't like that normal definition of that word for xyz application because .......... But you can't ever say a definition is wrong. If you don't like the word use a different one or make up your own word/ phrase then define it.

Edited August 23, 2011 by pantheory

[DrRocket]

To keep the calculation simple let's consider the case of a constant force applied to a mass starting from rest. Then

 

[math]F=ma[/math], [math] d=\frac {1}{2} at^2[/math], [math] v= \frac {d}{t}[/math] and [math] a = \frac {v}{t}[/math]

 

So

 

[math] F \times d = ma \times \frac {1}{2} at^2 = \frac {1}{2} ma^2t^2=\frac {1}{2} m \frac {v^2}{t^2} t^2 = \frac {1}{2} m v^2[/math]

 

Note that no other mechanism and no notion of "internal energy" are involved. The kinetic energy arises quite simply from the application of the force[math] F[/math] to the mass [math]m[/math].

 

You can gussy this up with line integrals and time-varying force, velocity and acceleration, but the end result is the same.

[finiter]

Note that no other mechanism and no notion of "internal energy" are involved. The kinetic energy arises quite simply from the application of the force[math] F[/math] to the mass [math]m[/math].

The relation, F = ma, is primarily a mathematical relation between force and energy. I agree. But when you say this relation says something about bodies, ie, a property of the bodies, then we can say that force imparts energy to bodies. But if you take the mathematical and the physical parts separately (that is what I suggest), then in my opinion, the mathematical part is correct, but the physical part requires some additional information. Where does the energy come from?

Force has only a mathematical definition. This being a speculative forum, I can argue, the mathematical relation is correct, but the mathematical definition is wrong. Force cannot impart energy, but if energy is made available, the body will follow the proposed relation.

 

 

As Dr. Rocket explained, the primary definition of energy in physic is a force applied to an object over a distance which defines the increased energy that the object being acted upon, receives. The totally different concept of "a force at a distance" is simply a force and nothing more until an action takes place concerning an applied force. There have been a number of arguments in physics concerning the validity of pulling forces at a distance such as gravity and magnetism, etc. But this is an entirely different subject. You can always argue about theoretical mechanics but not definitions. You can say I don't like that normal definition of that word for xyz application because .......... But you can't ever say a definition is wrong. If you don't like the word use a different one or make up your own word/ phrase then define it.

The concept of force is simple. But in physics, force has only a mathematical definition. Being a speculative forum, I say that definition is wrong, though the mathematical relation is valid provided we supply enough energy. Based on my theory, real forces like gravity, electrostatic force and magnetic force exists as a reaction to the energy possessed. Energy possessed acts as a pseudo force.

[swansont]

The relation, F = ma, is primarily a mathematical relation between force and energy. I agree. But when you say this relation says something about bodies, ie, a property of the bodies, then we can say that force imparts energy to bodies. But if you take the mathematical and the physical parts separately (that is what I suggest), then in my opinion, the mathematical part is correct, but the physical part requires some additional information. Where does the energy come from?

Force has only a mathematical definition. This being a speculative forum, I can argue, the mathematical relation is correct, but the mathematical definition is wrong. Force cannot impart energy, but if energy is made available, the body will follow the proposed relation.

 

 

 

The concept of force is simple. But in physics, force has only a mathematical definition. Being a speculative forum, I say that definition is wrong, though the mathematical relation is valid provided we supply enough energy. Based on my theory, real forces like gravity, electrostatic force and magnetic force exists as a reaction to the energy possessed. Energy possessed acts as a pseudo force.

 

Mechanical Work has a specific definition. If you want to change the model, you have to come up with new terminology. The model works, and all of it fits together with the given definitions — we have a self-consistent framework.. If you change the terms the model fails, even if you don't see the failure immediately.

 

You ask where the energy comes from. Using these definitions, energy is conserved. If you change them, that may not be the case. Conservation of energy is an exceedingly useful concept.

 

Objects can have energy and yet exert no force. Newton's first law indicates this.

[finiter]

Mechanical Work has a specific definition. If you want to change the model, you have to come up with new terminology. The model works, and all of it fits together with the given definitions — we have a self-consistent framework.. If you change the terms the model fails, even if you don't see the failure immediately.

 

You ask where the energy comes from. Using these definitions, energy is conserved. If you change them, that may not be the case. Conservation of energy is an exceedingly useful concept.

 

Objects can have energy and yet exert no force. Newton's first law indicates this.

I do agree with you, except with the argument that the model will fail ultimately. In the case of mechanical work, the bodies are in contact, and so the energy may be coming from the surroundings. Whether the energy comes from the surroundings or is imparted by the mechanical force, the energy is conserved. There is just a minor change in how the situation is viewed. But in the case of force acting at a distance, for example, the earth- moon system, I propose that gravitational force does not impart any energy to the moon either in the form of virtual gravitons or in any other way. Any change in the speed of the moon is due to transfer of energy from inside the moon.

 

I agree that if we change anything arbitrarily in the model, the model will fail, either immediately or in some other area which is not immediately visible. So the changes should come in a package to cover all the areas. The proposal that force does not impart energy is part of such a package, the basic assumption being energy is a finite quality of matter like mass and volume.

 

What I have said about the second law is correct for the first law also. It is also purely mathematical. The first law does not say anything about the nature of a physical body such as: whether a physical body can remain at rest; whether the body, if left alone, will move along a straight line; whether the body can attain the speed of light; etc. I think Newton considered it to be primarily mathematical, otherwise he would not have termed it 'pricipia mathematica'. However, Newton's laws can be used to calculate the effect of motion and forces, but the inherent physical nature of the bodies have to be separately defined. Newton's laws being mathematical can never be violated, whether the speed is zero or greater than zero. Any observation that seems to violate Newton's laws is consequent on the interpretation that Newton's laws are physical.

 

Any moving body has gravity, and gravity will always be acting.

Edited August 25, 2011 by finiter

[swansont]

I do agree with you, except with the argument that the model will fail ultimately. In the case of mechanical work, the bodies are in contact, and so the energy may be coming from the surroundings. Whether the energy comes from the surroundings or is imparted by the mechanical force, the energy is conserved. There is just a minor change in how the situation is viewed. But in the case of force acting at a distance, for example, the earth- moon system, I propose that gravitational force does not impart any energy to the moon either in the form of virtual gravitons or in any other way. Any change in the speed of the moon is due to transfer of energy from inside the moon.

 

I agree that if we change anything arbitrarily in the model, the model will fail, either immediately or in some other area which is not immediately visible. So the changes should come in a package to cover all the areas. The proposal that force does not impart energy is part of such a package, the basic assumption being energy is a finite quality of matter like mass and volume.

 

Which is why you need to change the terminology.

 

What I have said about the second law is correct for the first law also. It is also purely mathematical. The first law does not say anything about the nature of a physical body such as: whether a physical body can remain at rest; whether the body, if left alone, will move along a straight line; whether the body can attain the speed of light; etc. I think Newton considered it to be primarily mathematical, otherwise he would not have termed it 'pricipia mathematica'. However, Newton's laws can be used to calculate the effect of motion and forces, but the inherent physical nature of the bodies have to be separately defined. Newton's laws being mathematical can never be violated, whether the speed is zero or greater than zero. Any observation that seems to violate Newton's laws is consequent on the interpretation that Newton's laws are physical.

 

Any moving body has gravity, and gravity will always be acting.

 

I think Newton was expressing things in mathematical terms which was revolutionary at the time. The first law does say those things, other than reaching c; Newton didn't know about that.

[finiter]

I think Newton was expressing things in mathematical terms which was revolutionary at the time. The first law does say those things, other than reaching c; Newton didn't know about that.

That is where I speculate. Newtons laws, including the gravitational law, were taken as physical laws and the present terminology is based on that. Actually these are mathematical laws. So it requires a new terminology based on physical properties of bodies. Physics has thus deviated from the right direction from the time of Newton. By changing that direction, it is possible to arrive at the theory of everything.