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From: Randy Poe on 23 Sep 2005 14:55 TomGee wrote: > Randy Poe wrote: > > TomGee wrote: > > > Randy Poe wrote: > > > > TomGee wrote: > > > > > It would be a pity if you were right, but you contradict yourself > > > > > immediately by saying above that force and momentum are equivalent. > > > > > > > > Where did I say that? I would have snipped more, but I wanted > > > > to leave all the stuff you quoted from me so you can point > > > > me to the passage where you think I said F = p. > > > > > > > If you think you did not say it. then just what do you mean by F=dp/dt? > > > > That force is the derivative of momentum with respect to time. > > > I see. And the relevance of that to our topic is ...? That force and momentum are not the same thing. That the equation F = dp/dt does not say that they are the same thing. That the discussion was whether I had said they were the same thing. Isn't the topic of discussion "momentum and force are the same thing"? > > For instance suppose p is a constant in time, say p = 5. > > The F = dp/dt = 0. Five and zero are not the same. > > > > Suppose p is increasing linearly in time, p = p_0 + b*t > > > > Then F = dp/dt = b, a constant. The constant b and the > > linearly increasing function p_0 + b*t are not the same. > > > > > Okay, so what? So p and dp/dt are not the same thing. So when I say F = dp/dt, I'm not saying F = p. So momentum and force are not the same thing. So momentum and force are related by the differential relationship, F = dp/dt. So actually working out dp/dt for some specific examples illustrates how very different momentum and force are for any given situation. - Randy
From: TomGee on 23 Sep 2005 15:10 Herman Trivilino wrote: > "TomGee" <lvlus(a)hotmail.com> wrote ... > > > Then, Herman, what does E=mc^2 mean to you? > > It means that mass is a form of energy. > > That's what we have been taught to think Terman, but it does not mean that at all. That is a "preconception" put in your mind by PD's stupid teachers who have been taught to sneer at their students ideas. They have convinced you to that's what it means because that's what they were taught too and they have been taught not to think for themselves. They taught you that it means mass is a form of energy and that if you try to say it doesn't then you are showing your inability to change your preconceived ideas. PD's circular arguments notwithstanding, it's a trick, donchasee? > > > When you are co-moving with respect to a composite body, the mass m that you > measure of the composite body consists of two parts. It is the sum of the > masses of each of the objects within the composite body PLUS the total > energy (divided by c²) of those objects. > > Two parts? Didja forget about the many atoms and their many parts? > > > In other words, when we measure the mass of a composite body we find that it > consists not only of the masses of the components, but also the total of > their energies. Thus we see that mass is just one of the many different > forms of energy. > > That is what it means to me. Thanks for asking. That is one of my favorite > questions to answer! > > If you use AE's shortened version of the formula you do not measure "the total of their energies", you only measure the mass and not it's momentum.
From: Herman Trivilino on 23 Sep 2005 15:51 "TomGee" <lvlus(a)hotmail.com> wrote ... >> > Then, Herman, what does E=mc^2 mean to you? >> It means that mass is a form of energy. > That's what we have been taught to think No it isn't. It's what I've been taught to think. > They taught you that it means mass is a form of energy and that if you > try to say it doesn't then you are showing your inability to change > your preconceived ideas. Uh..., I'd have to say that most of the teaching that I've been exposed to didn't make this at all clear to me. It's an understanding I've come to after studying the subject, talking about it with others, reading about it in textbooks and journals. >> When you are co-moving with respect to a composite body, the mass m that >> you >> measure of the composite body consists of two parts. It is the sum of >> the >> masses of each of the objects within the composite body PLUS the total >> energy (divided by c?) of those objects. > Two parts? Didja forget about the many atoms and their many parts? No. I didn't. My argument in no way restricts it to two parts. > If you use AE's shortened version of the formula you do not measure > "the total of their energies", you only measure the mass and not it's > momentum. You asked the question. I answered it. When you measure their energies you do indeed measure "only" the mass. That's my point. That's what is meant by the statement that mass is a form of energy. ----== 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: Herman Trivilino on 23 Sep 2005 15:54 "TomGee" <lvlus(a)hotmail.com> wrote ... >> He just told you what I meant. I didn't say F = p, I said F is the >> time rate of change of p. >> >> > And the relevance of that to out topic is...? You asked. We answered. It doesn't get any more relevant than that. ----== 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: PD on 23 Sep 2005 16:01
TomGee wrote: > Herman Trivilino wrote: > > "TomGee" <lvlus(a)hotmail.com> wrote ... > > > > > Then, Herman, what does E=mc^2 mean to you? > > > > It means that mass is a form of energy. > > > > > That's what we have been taught to think Terman, but it does not mean > that at all. That is a "preconception" put in your mind by PD's stupid > teachers who have been taught to sneer at their students ideas. Hey, look at that, TomGee is talking about me in the 3rd person as though I'm not there, something he finds repellingly rude. PD |