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From: Randy Poe on 21 Sep 2005 13:45 TomGee wrote: > odin wrote: > > What makes you think that perpetual motion is not possible in the limit as > > friction tends to zero? > > > > > What makes you think the restrictions against perpetual motion have to > do with friction? (Hint: They have to do with entropy.) And what makes you think an object moving at constant velocity without consuming energy, without the presence of an external force, violates the laws of thermodynamics? (Hint: the second kind of perpetual motion machine has to do with entropy. The first kind has to do with conservation of energy, which has a lot to do with friction). - Randy
From: TomGee on 21 Sep 2005 14:04 Randy Poe wrote: > TomGee wrote: > > If no force is present, that constitutes perpetual motion, which does > > not exist in our universe. > > Is that what this is about? Your misunderstanding of the > "perpetuum mobile"? That's a common enough misunderstanding. > Let me correct your misunderstanding: > > (http://en.wikipedia.org/wiki/Perpetual_motion) > A "perpetual motion machine" is impossible, because it > violates the laws of thermodynamics. There are two kinds > of perpetual motion machine, or perpetuum mobile. > > a. A perpetuum mobile of the first kind produces at least > as much work as it consumes. For instance, it consumes zero > energy, but produces nonzero work. This violates the conservation > of energy. > > b. A perpetuum mobile of the second kind is a 100% efficient > heat engine, converting heat into work with 100% efficiency. > That this is impossible requires more subtle proof, but > ultimately has to do with the 2nd law of thermodynamics. > > Yes, it constitutes perpetual motion. No, perpetual motion is > NOT impossible in our universe, only perpetual motion which > produces work. > > Did you forget to name all those perpetual motions which are not impossible? As you know or should know, Wiki wiki is not a reliable source because it can edited by anyone and apparently it has been, judging by the things one can read in it. However, my objection has to do with entropy, where all objects move toward the chaos of equilibrium. _Any_ perpetual motion violates that concept, so for your interpretation of Newton (which is false) claiming perpetual motion must first overthrow entropy and the arrow of time for it to be true. > > > How do you overcome that? > > There's nothing to overcome. > > Yes, there is. > > > > Do you deny that is perpetual motion? > > Of course not. > > > Do you claim that it exists in that one instance? > > I claim that it exists in all instances in which there is motion > and no external force acting. > > What about in an instance of motion where an internal force is acting? > > > > > Do you think an energy supply is needed? What's keeping Voyager > > > going, way out there beyond the solar system, now that its fuel > > > is gone? > > > > > Well, it could not be perpetual motion, could it? > > Of course it could. > > No, it could not be that unless it violates entroy. > > > > As I say above, it's > > momentum keeps it going now, but it won't always. > > Newton's third law, translated into modern terminology, says > that momentum only changes when there is an external force. > > No, it says the _velocity_ will change only when there is an external force. Then it says the velocity will not change "due to its inherent force". They left that out when they taught us the first law so they lied to us by omitting it. But I accept your definition of momentum which includes velocity because they relate to the same thing. Momentum is a numerical quantity related to the mass and its velocity and it is a force related to the mass and its velocity. > > > If there are no external forces, the momentum will never > change and the "momentum will keep it going" forever. > > Your misunderstanding of the phrase "perpetual motion > machine" is as I said fairly common. See threads such as > "is the atom a perpetuum mobile". > > - Randy > > Your misunderstanding of perpetual motion as it relates to entropy is unfortunately all too common.
From: Randy Poe on 21 Sep 2005 14:16 TomGee wrote: > Randy Poe wrote: > > TomGee wrote: > > > If no force is present, that constitutes perpetual motion, which does > > > not exist in our universe. > > > > Is that what this is about? Your misunderstanding of the > > "perpetuum mobile"? That's a common enough misunderstanding. > > Let me correct your misunderstanding: > > > > (http://en.wikipedia.org/wiki/Perpetual_motion) > Did you forget to name all those perpetual motions which are not > impossible? > > As you know or should know, Wiki wiki is not a reliable source because > it can edited by anyone and apparently it has been, Oh, good grief. I chose the wikipedia link among the many possibilities because I thought it carried a little more credence. Wikipedia articles on technical subjects tend to be pretty good. But very well... No, I'll tell you what. You find ME a reference that says motion of an object forever without the influence of an external force, and without doing any work, violates some law of thermodynamics. > things one can read in it. However, my objection has to do with > entropy, where all objects move toward the chaos of equilibrium. Uh-huh. Now tell me why this kind of motion has something to do with entropy, and what law of thermodynamics rules it out. > _Any_ perpetual motion violates that concept, Really? Show me where the violation is here. - Randy
From: Herman Trivilino on 21 Sep 2005 14:25 "TomGee" <lvlus(a)hotmail.com> wrote ... >> So perhaps your "internal force" is a different kind of thing >> from what we call forces. It is always there, there is no such >> thing as "absence of internal force", and therefore there is >> no experiment which can determine the effect of your "internal >> force". > Oh yes there is. What followed was NOT a description of an experiment. > [...], then we can safely and simply assume > that my internal force is nothing more than the kinetic energy of the > body. Force and energy can't be the same. They are of different dimension! > My model contends that energy is a force. It's automatically rejected, out of hand. Force is a gradient of energy. Put informally, force is a measure of how an energy (potential energy) changes with position. Forces are interactions between objects. Internal forces exist only for composite bodies -- they are forces between the objects that make up the composite body. > A force is "power or strength: the power, strength, or energy that > somebody or > something possesses" > Microsoft? Encarta? Reference Library 2005. ? 1993-2004 Microsoft > Corporation. All rights reserved. That's a layman's definition from a layman's reference. It's contradicted by even the most elementary of introductory physics references. Power is a rate of energy (has dimensions of energy over time). Force is a gradient of energy (has dimensions of energy over distance). It is perhaps the most fundamental facet of natural science that quantities with different dimensions can't be compared. It's meaningless to say they're the same, or equal. ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =----
From: TomGee on 21 Sep 2005 17:12
Okay, Randy, but this first: Work is a purposeful physical effort directed toward doing something. It is a means for energy transfer. Entropy is a measure of the energy in a system or process that is unavailable to do work. Perpetual Motion is a long-held concept of a system that could operate indefinitely, once started, without any further expenditure of outside energy. Such a system is not in accord with the fundamental laws of physics. Any system will run down when left to itself, through various forms of attrition. On the subatomic level, perpetual motion may be said to be observed in the motion of electrons around a nucleus. Even here, however, the concept of entropy (the second law of thermodynamics) views the universe as a whole as incapable of perpetual motion. Microsoft® Encarta® Reference Library 2005. © 1993-2004 Microsoft Corporation. All rights reserved. Now then, the first law of thermodynamics holds heat, work, and energy to be equivalent, being a law of energy conservation. It states that the amount of heat put into a system and the amount of work done on the system increase the internal energy in the system, thus making heat and work mechanisms by which systems exchange energy. In any machine, some amount of energy is converted into work; therefore, no machine can exist in which no energy is converted into work, and that would be a P-M machine of the first kind. The second law defines entropy and states that the disorder of an isolated system can never decrease. Such a system reaches equilibrium when it can no longer undergo change. It states that without doing some work, heat (and thus, energy) cannot be transferred from an area of lower heat (energy) to one of higher heat (energy). Any machine that does that violates the second law and is a -M machine of the second kind. Now, let's go to Newton's first law of inertial motion. Da Vinci thought of it about 100 years before Galileo, who proposed that an isolated body will continue moving at constant velocity forever. Along came Newton and he copied Galileo's and Da Vinci's work verbatim and he was acknowledged as the inventor of that idea. From there, the entire work was corrupted by translations that have Newton saying a body needs no force to keep it going forevermore, and we were all taught that lie and apparently brainwashed with it given the stiff reluctance by some to acknowledge the lie. Now here before the Court of Posterity comes Randy Poe, who claims some P-M machines can exist but who cannot name one. The concept of entropy claims that a P-M machine of the first kind is not possible and that a P-M machine of the second kind violates the second law of thermodynamics. Which kind does the Claimant proposes exists? The Claimant alleges that an isolated body having no external or internal forces acting upon it will continue to move in a straight line at uniform motion forevermore, basing his claim that Newton said that very same thing and everyone else in the world except yours truly the Litigant believes the same as the Claimant. Since there is no place in the world where anyone believes as the Litigant believes, a change-of-venue motion was denied the Litigant. Now it becomes necessary to establish the type of P-M machine which the Claimant claims can exist. Claimant states that P-M of the second kind is not impossible, only P-M which produces work is impossible. Our definition of work above states that work is an act of doing something, and the second law above makes work, heat, and energy equivalent. Thus any P-M doing work, making heat, and/or using energy violates the second law. Litigant rests. |