Motion
in [Physics]
|
Prev: Free fall
Next: 50% OF POPULATION BELOW AVG IQ!
From: Paul Stowe on 24 Sep 2005 23:22 On 23 Sep 2005 15:49:13 -0700, "TomGee" <lvlus(a)hotmail.com> wrote: > Well, thanks for your input, Paul. Would you be able to > answer my question to Randy? Herman tried but he had no > luck with it either. Or maybe you can clarify the question > for them as you have clarlfied the equation which Randy > claims "relates" to our topic. It all stems back to this, Randy Poe: "That's correct. There is no force that keeps bodies in motion. Forces only act to change motion." True... Your response: "So you agree with PD and Worms. What else is new? They only believe that because they were taught to believe that. Anyone with a real brain would be able to support such a wild statement, but I see you offered none, so that's just your opinion." However, this make no sense. Indeed, momentum IS, by definition, any inertial motion. And force, (dp/dt) isn't inertial. However, your claim that bodies in 'real space' are, in fact, NOT in true inertial motion is also true. Thus, there are forces acting to slow the down. The most primal of which is the CMBR. Thus, to 'truly' maintain a constant speed one would have to counter the drag forces. However, you'd be a very LONG time dead before you ci=ould measure' the effect. Thus the subtle but real difference between the 'actual' and idealized'. Paul Stowe
From: TomGee on 25 Sep 2005 01:35 Randy Poe wrote: > TomGee wrote: > > Randy Poe wrote: > > > So the topic is still "Tom informed me I said force and momentum > > > are equivalent", and you amplified it to say that "F = dp/dt > > > is a statement that force and momentum are equivalent". > > > > > > > > I did not amplify it. > > OK. > > > You're the one who said it "relates" force and > > momentum. > > Yes, I did. > > > I simply asked you to explain how you think it relates to them. > > Well, "relates force and momentum" and "relates TO force and > momentum" aren't quite the same thing, but I'll tell you how it > does both. > > Well, I wasn't sure which way you meant it, so I asked. > > > The equation F = dp/dt relates to force and momentum because it > is an equation in terms of force F, and momentum p. > > It relates force and momentum, i.e., tells you how force and > momentum are related, by telling you that force is the time > rate of change of momentum. > > No, that is not what it tells you. It is an equation - a math construct - telling you that the force F is _equal_ to the time rate of change of the given momentum, exactly like E=mc^2 tells you not that energy is mass, but that the energy E is equal to the given mass multiplied by c^2. Like the differences in your "relates" and "relates to" not being quite the same thing, our two statements are not quite the same thing either. And you know that. Here are 3 definitions of momentum, all common terms in use by laypersons and scientists alike in the various ways it can be defined. None of them define it like you do above, but yours is as common and as valid as the others as an equation useful for determining the amount of force in a given momentum. You cannot avoid seeing that translates literally into what I said, that force and momentum are equivalent. See the F on the one side of the = sign? And the other stuff on the other side? That means, simply, that if you calculate everything on the right side, it will tell you how much force is involved. Therefore, if I want to know how much force is involved in a given momentum, I have that equation handy. "1. capacity for progressive development: the power to increase or develop at an ever-growing pace The project was in danger of losing momentum. 2. forward movement: the speed or force of forward movement of an object the momentum gained on the downhill stretches of the course 3. physics measure of movement: a quantity that expresses the motion of a body and its resistance to slowing down. It is equal to the product of the body's mass and velocity. Symbol p". Microsoft® Encarta® Reference Library 2005. © 1993-2004 Microsoft Corporation. All rights reserved. Now in 1., above, momentum is used to mean a "power". In 2., it is used as a force OR a speed, and in 3., it is a quantity, just like in your equation. Here's another definition: A property of a moving body that determines the length of time required to bring it to rest when under the action of a constant force or moment. Broadly impetus. That too is an explanation of momentum as your equation uses the term. Now impetus is defined as: a driving force. The property possessed by a moving body in (sic) virtue of its mass and its motion. That sounds like yet another way to define momentum, no? Yet you dare to say that the only valid way to use the terms force and momentum is other than the way they are used in my examples? You claim the right to demand the use of those two terms only in the way your equation defines it? Even while the rest of the world defines them in some many other acceptable ways? Who the hell do you think you are? Oh, I know you as the one who mistakenly linked Newton's laws 2 and 3 to gravitation, confused law 2 with law 3, claimed force and acceleration are not related to law 3, and that a force only pushes or pulls depending on whether the situation relates to the macroscopic or the microscopic world. There are many more of these wrong and silly beliefs you hold which are revealed in your posts just in this ng alone. > > > > I did not ask you for that. And you have not yet answered my question > > of what you meant by the statement. > > By the statement F = dp/dt, I mean that force is the time rate > of change of momentum. > > In what way is that not an answer to the question? > > It is an equation that tells you, given an expression for momentum, > how to find out the corresponding force. It tells you, given > a force, how to find out its effect on momentum. > > High-sounding words, but they're nonsense. What is "an expression for momentum" if not just a quantity? It does NOT tell you how to find out a force's effect on momentum! I knew you did not know what your equation means! You memorized it all and now consider yourself a learned member of high society! Just like you are one duly appointed to see that no one here uses terms other than in the way you want them to be used, I am the one appointed to point out to the world the naked emperors as they parade around with their high and mighty noses in the air! Tell us, your Nakedness, just how do we find out a force's effect on momentum from F=dp/ dt? You are so funny! > > > > Why, if you cannot decipher the very very very simple question? > > It's a very simple equation. There are only three things to explain > in it. It contains force F, momentum p, and the time rate of change > operation d/dt. So when I tell you that this equation says that > force is the time rate of change of momentum, I have explained > every single symbol in the equation. Furthermore, I gave a couple > of examples of momentum vs time and the force that would give > rise to that behavior, using this equation. > > What, in your opinion, have I not explained about this equation? > > But I knew all that already just by reading Encarta. What Encarta failed to teach me was how to find the effect a force has on momentum using your famous equation.
From: TomGee on 25 Sep 2005 01:41 PD wrote: > TomGee wrote: > > Yata yata yata. Total nonsupport for everything you said. Why should > > anyone take your opinion on this? If everything Encarta says is wrong, > > you are accusing eminent scientists of being stupid. Where does that > > leave you who claims to know more than they but who never gives > > anything more than your own opinion? > > The definition of a perputual motion machine as Encarta defines it is > in conflict with the definition of a perpetual motion machine as almost > any reputable physics book would define it. A number of references from > reputable physics books would demonstrate that. > > Well, let's have them refs, PD, time's awasting! > > > The fact remains, however, that TomGee has already stated that a very > large number of references written by eminent physicists would not be > enough to convince him, as those would be all unsupported opinion (in > his judgement). > > Liar liar pants on fire! Not my fault you can't understand what you read! > > > He has already demonstrated that he would rather trust > Encarta's unsupported definitions, as he considers them to be written > by eminent scientists, also an unsupported claim, and he considers > those authors to have higher eminence (also an unsupported claim) than > the authors of the physics books. > > You're the only eminent scientist who posts unsupported opinions here, PD, unless you know of some others I don't recognize.
From: TomGee on 25 Sep 2005 01:47 Why don't you do that for him, step..., and let us know when you find one of them quotes where I changed words and phrases in it. Like all these other numbnuts, you post wild opinions without any support for them and expect to get away with it. You think readers are so stupid as to believe you when you don't give an example to prove your charge? Why didn't you give an example, anyway? Was it because you don't have one or because you're stupid enough to think the readers will believe every one of your opinions?
From: "Androcles" <Androcles@ on 25 Sep 2005 10:00
"TomGee" <lvlus(a)hotmail.com> wrote in message news:1127612309.681622.150770(a)g49g2000cwa.googlegroups.com... | > > Now let's have some of them P-Ms you spoke of earlier in our | > > discussion. | > | > No idea what I might have said that you are reading as "P-Ms". | > | > | Um, we discussed "perpetual motion machines"? Remember? Oh...I thought you were discussing Pre-Menstrual Syndrome. Androcles |