Motion
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From: TomGee on 9 Oct 2005 10:13 No, donstockba... I do not advocate all that at all. What is in place is not working right and it needs fixing. I recommend a General Phd level where there is no recognition of narrowing in any subject but rewards broad knowledge in at least three fields within the discipline where "broad" is defined to an Masters level. A GPhd would not preclude a Phd in any of the three or other disciplines, but for that to be attainable the GPhd must be earned first. Think what great scientists that would produce for a nation! A BA is a review of high school subjects plus tempting tidbits to dabble in the last two years. A Masters is a joke as free slaves for professors plus a coin toss into the narrowest of fields to win a Phd. Did not all you physicists feel that way about it in school?
From: Randy Poe on 9 Oct 2005 17:45 TomGee wrote: > Randy Poe wrote: I said this: > > I'm saying that work is done by the component of force > > in the direction of motion. > > > > If the force is ALWAYS at right angles to the motion, no > > work is done. And Tom, apparently in reply, said this: > Ah yes, so then work is being done by the component of force which you > claim is a non-existent force? I can't connect this to what I said since I said nothing about (a) work being done (I was explicitly talking about work NOT being done) and (b) a non-existent force. > What force makes the work in moving the body? There is no "work" being done in moving a body at constant velocity in the absence of any external forces. If I am not changing the KE of a body, I don't need to add any energy to it. If I do work on a body, I will change its energy. If it has 5 Joules now and I do 1 Joule of work, it will have 6 Joules. If it has 5 Joules now and I want it to have 5 Joules an hour from now, the amount of work I need to do on it is 5 J - 5 J = 0. > Is it KE? Well, let's see. KE is not a force, I don't need a force, and I don't need to do any work. So I don't know what "it" might refer to. > Could that be the body's inherent force? You are asking if KE is a candidate for a thing which doesn't exist. I don't need any candidates for a thing which doesn't exist. > But if it > is, that force could not be one of your unmentioned perpetual motion > systems, could it, since it is doing work? No, nothing is doing work on a body in constant-velocity motion. You've garbled the definition of perpetual motion machine even worse than before. A perpetual motion machine must be able to DO work. A body in a state of constant motion in the absence of forces is neither doing work, nor having work done to it. > The answer is of course > that the KE of the body is exhibited by its momentum force KE is not momentum, momentum is not force, KE is not force. > > There's nothing to study. > > > Ah but there is Randy, you need to study physics a little more > generally to get out of the narrow hole you've gotten yourself into. > That's what's wrong with education - the more you get, the narrower a > hole it puts you into while the world in general goes on without you > (TomGee). Please point me to a place where Newton's Laws or Conservation of Energy fails to describe the system correctly. - Randy
From: TomGee on 10 Oct 2005 08:14 Randy Poe wrote: > TomGee wrote: > > Randy Poe wrote: > > I said this: > > > I'm saying that work is done by the component of force > > > in the direction of motion. > > > > > > If the force is ALWAYS at right angles to the motion, no > > > work is done. > > And Tom, apparently in reply, said this: > > > Ah yes, so then work is being done by the component of force which you > > claim is a non-existent force? > > I can't connect this to what I said since I said nothing about > (a) work being done (I was explicitly talking about work NOT > being done) and > (b) a non-existent force. > > Yes, you did: (a)"I'm saying that work is done by the component of force in the direction of motion" In English that means _when and if ever_ work is done, it is then being done by the "force" which you mentioned but failed to name. It's clear that you were talking about a force that does work in a body's "direction of motion" in support of your statement that no work is being done by the right angle force on an orbiting object wrt its KE. That is correct of course but you did not think it through well enough to notice that your unnamed "...component of force in the direction of motion" is the (b)"non-existent" force which you et al claim is not needed by sole objects having zero net external forces to move at CV. Check. > > > > What force makes the work in moving the body? > > There is no "work" being done in moving a body at constant > velocity in the absence of any external forces. > > But you said above that work is done by "the component of force in the direction of motion". What force are you talking about? You're afraid that naming it will cause you to lose this debate, aren't you? Well, the news is that you lost it up already anyway but admitting there is such a force that moves a body "in the direction of motion". Mate. > > > If I am not changing the KE of a body, I don't need to add > any energy to it. > > Who said you did? > > > If I do work on a body, I will change its energy. If it has > 5 Joules now and I do 1 Joule of work, it will have 6 Joules. > If it has 5 Joules now and I want it to have 5 Joules an > hour from now, the amount of work I need to do on it is > 5 J - 5 J = 0. > > > Is it KE? > > Well, let's see. KE is not a force, I don't need a force, > and I don't need to do any work. So I don't know what "it" > might refer to. > > My "it" refers to your unnamed so-called "component of force" which performs work to move a body "in the direction of motion". > > > > Could that be the body's inherent force? > > You are asking if KE is a candidate for a thing which > doesn't exist. I don't need any candidates for a thing > which doesn't exist. > > Then what is the mysterious "component of force" which you claim performs work to move a body? > > > > But if it > > is, that force could not be one of your unmentioned perpetual motion > > systems, could it, since it is doing work? > > No, nothing is doing work on a body in constant-velocity > motion. You've garbled the definition of perpetual motion > machine even worse than before. > > No, no garbling at all except by your non-existent non-work-performing P.M. machine which you have been unable to display. You said that work is done on a body "in the direction of motion" by some component of force. You contradicted yourself and refuse to admit it. > > > A perpetual motion machine must be able to DO work. > > Yet you claimed that there are some that do not. Which is it? > > > A body > in a state of constant motion in the absence of forces is > neither doing work, nor having work done to it. > > That's what all of us have had ingrained into our skulls and it will be very difficult for some to accept the fact that we were sold a pig in a poke which I have discovered is not kosher. > > > > The answer is of course > > that the KE of the body is exhibited by its momentum force > > KE is not momentum, momentum is not force, KE is not force. > > Yes, they are, and the sooner you come to grips with that, the sooner you will stop climbing the walls. > > > > > There's nothing to study. > > > > > Ah but there is Randy, you need to study physics a little more > > generally to get out of the narrow hole you've gotten yourself into. > > That's what's wrong with education - the more you get, the narrower a > > hole it puts you into while the world in general goes on without you > > (TomGee). > > Please point me to a place where Newton's Laws or Conservation > of Energy fails to describe the system correctly. > > Gee, I don't know - the space-time continuum?
From: Randy Poe on 10 Oct 2005 09:39 TomGee wrote: > > Please point me to a place where Newton's Laws or Conservation > > of Energy fails to describe the system correctly. > > > > > Gee, I don't know - the space-time continuum? Been watching Star Trek? Picked up a new vocabulary word? The "space-time continuum" is where we live and use Newton's Laws every day. NASA uses them to plot trajectories to very high precision. You probably meant to say something clever about relativity, but you're wrong. In the absence of forces, particles still follow straight lines (now called geodesics), force is still equal to dp/dt, and momentum is still conserved. - Randy
From: Randy Poe on 10 Oct 2005 10:02
TomGee wrote: > Randy Poe wrote: > > TomGee wrote: > > > Randy Poe wrote: > > > > I said this: > > > > I'm saying that work is done by the component of force > > > > in the direction of motion. > > > > > > > > If the force is ALWAYS at right angles to the motion, no > > > > work is done. > > > > And Tom, apparently in reply, said this: > > > > > Ah yes, so then work is being done by the component of force which you > > > claim is a non-existent force? > > > > I can't connect this to what I said since I said nothing about > > (a) work being done (I was explicitly talking about work NOT > > being done) and > > (b) a non-existent force. > > > > > Yes, you did: (a)"I'm saying that work is done by the component of > force in the direction of motion" In English that means _when and if > ever_ work is done, it is then being done by the "force" That's correct. And it's being done by the component of force which is in the direction of motion. > which you mentioned but failed to name. Eh? It's a general statement. When work is being done, it's being done by the component of force in the direction of the motion. What "name" is missing there? > It's clear that you were talking about a > force that does work in a body's "direction of motion" Yes, when work is being done. > in support of your statement that no work is being done by > the right angle force on an orbiting object Right, no work is being done in that case. > wrt its KE. That's meaningless. What does "work wrt its KE" mean? > That is correct of course but you did not think it through well enough > to notice that your unnamed "...component of force in the direction of > motion" is the (b)"non-existent" force which you et al claim is not > needed by sole objects having zero net external forces to move at CV. That's right, I didn't think that there is a component of force in the case of zero force When the force is zero, all components are zero. When no work is being done, as in the case of constant velocity, there are no external forces present. When there are no external forces, there is no work being done, and KE is constant. > > > What force makes the work in moving the body? > > > > There is no "work" being done in moving a body at constant > > velocity in the absence of any external forces. > > > But you said above that work is done by "the component of force in the > direction of motion". Yes, and in the case of constant velocity, there is no force. > What force are you talking about? The force that is present when work is being done, KE is changing, and velocity is changing. None of which is true in the case of constant velocity. > You're afraid that naming it will cause you to lose this > debate, aren't you? No, I can name the force in the case of constant velocity: it is called "zero". - Randy |