Ballistic Theory, Progress report...Suitable for 5yo Kids
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From: George Dishman on 22 Aug 2005 14:39 "Henri Wilson" <H@..> wrote in message news:v31ig1tdf472qd5oroliki57bqtsv2h4ea(a)4ax.com... > On 20 Aug 2005 08:57:07 -0700, "Jeff Root" <jeff5(a)freemars.org> wrote: > >>George Dishman replied to Jim Greenfield: >> >>> The whole point of splitting the explanation into >>> two stages was to try to help you grasp what is >>> to me obvious, the forces are produced solely by >>> the motors driving the shaft. Imagine instead the >>> shaft was horizontal. You attach a motor at each >>> end and drive them at different speeds and the >>> same effect occurs. The energy 'appears' because >>> you have to connect the motors to a source of >>> power if they are to turn the shaft. >> >>Jim hasn't explained how the "clocks" are supposed to be >>connected to the axle. If the axle itself is meant to keep >>time like a clock (say, like the shaft which turns a clock's >>second hand), then he is definitely talking about a single >>clock. Yet he insisted that there were two clocks, one at >>the bottom and one at the top. I suspect that he only meant >>that there were pointers or "clock hands" at the bottom and >>top of the axle, and that the only motor driving it is the >>one at the bottom, but until he says what he has in mind, >>we can only speculate. >> >>>> Well my belief is, that the axle will not get twisted >>>> around and around just because 'time' is passing >>>> (and the axle spinning) >>> >>> The fact is that it would. >> >>If you think the axle would become twisted, then I'm quite >>sure that your understanding of the thought experiment setup >>is different from his. With only one motor connected to the >>axle, it would not become twisted. Although he has said >>there are two clocks connected to the axle, he has said only >>one motor is driving it. He needs to clarify that confused >>description. >> >> -- Jeff, in Minneapolis > > Jim has every right to assume that most contributors to this NG have some > kind > of intelligence which enables them to occasionally apply their own > deductive > powers in cases when every minute detail is not spelled out as though for > a 2yo > kid.. The problem is precisely that though, he asked a question which contained contradictory statements, first that the shaft was driven at both ends and secondly that it was driven only from the bottom. Jeff and I filled in the blanks but we took different parts as our starting point. It is reasonable to keep the details to a minimum but the question has to be consistent if you want consistent replies. George
From: George Dishman on 22 Aug 2005 14:45 "Henri Wilson" <H@..> wrote in message news:2koig1pve4pnr65p78s3afggrvqiv62mog(a)4ax.com... > On 21 Aug 2005 20:04:33 -0700, "Jeff Root" <jeff5(a)freemars.org> wrote: > >>Henri Wilson replied to Jeff Root: >> >>>> George Dishman replied to Jim Greenfield: >>>> >>>>> The whole point of splitting the explanation into >>>>> two stages was to try to help you grasp what is >>>>> to me obvious, the forces are produced solely by >>>>> the motors driving the shaft. Imagine instead the >>>>> shaft was horizontal. You attach a motor at each >>>>> end and drive them at different speeds and the >>>>> same effect occurs. The energy 'appears' because >>>>> you have to connect the motors to a source of >>>>> power if they are to turn the shaft. >>>> >>>> Jim hasn't explained how the "clocks" are supposed to be >>>> connected to the axle. If the axle itself is meant to keep >>>> time like a clock (say, like the shaft which turns a clock's >>>> second hand), then he is definitely talking about a single >>>> clock. Yet he insisted that there were two clocks, one at >>>> the bottom and one at the top. I suspect that he only meant >>>> that there were pointers or "clock hands" at the bottom and >>>> top of the axle, and that the only motor driving it is the >>>> one at the bottom, but until he says what he has in mind, >>>> we can only speculate. >>>> >>>>>> Well my belief is, that the axle will not get twisted >>>>>> around and around just because 'time' is passing >>>>>> (and the axle spinning) >>>>> >>>>> The fact is that it would. >>>> >>>> If you think the axle would become twisted, then I'm quite >>>> sure that your understanding of the thought experiment setup >>>> is different from his. With only one motor connected to the >>>> axle, it would not become twisted. Although he has said >>>> there are two clocks connected to the axle, he has said only >>>> one motor is driving it. He needs to clarify that confused >>>> description. >>> >>> Jim has every right to assume that most contributors to this >>> NG have some kind of intelligence which enables them to >>> occasionally apply their own deductive powers in cases when >>> every minute detail is not spelled out as though for a 2yo >>> kid.. >> >>Sure. But it still isn't clear what he meant by "two clocks", >>or how those two clocks are connected to the axle. George >>guessed that each of the two clocks has its own motor or other >>mechanism to make it run, since that is what makes them clocks. >>I, on the other hand, guess that Jim was talking about clock >>hands at each end of the axle, being driven by the rotation >>of the axle, which is, in turn, driven at its bottom end. >> >>George's guess may be right, or mine, or maybe both are wrong >>and Jim's concept is something else. Only Jim can say. > > If you have been following my discussion with George Dishman, you would > know > what Jim and I mean. > > The rotation of the shaft itself can be used as a fixed time duration > reference. ... That's not what Jim said once I clarified the question, he asked where the energy came from to twist the axle: <jgreen(a)seol.net.au> wrote in message news:1124523631.189668.274450(a)o13g2000cwo.googlegroups.com... > > G'day George, > > You seem to grasp that there is a problem for GR, because the > forces/energy involved to produce said breakages/twisting are due to > separation by distance ONLY (which causes the gravitational difference > at top and bottom. > Where and why should such energy "appear", just because the top of the > rotating axle is "up there"?? How would the forces "know" what to apply > to a STATIONARY axle?? The answer of course is trivial, it comes from whatever powers the clocks. George
From: Henri Wilson on 22 Aug 2005 18:58 On Mon, 22 Aug 2005 10:40:34 +0200, "Paul B. Andersen" <paul.b.andersen(a)deletethishia.no> wrote: >Henri Wilson wrote: >> The rotation of the shaft itself can be used as a fixed time duration >> reference. >> Its period doesn't need to be measured by any clocks. It can be assigned the >> value of ONE time unit. If each of its ends is connected to a rotating 'hand', >> the two hands must always be rotating at the same angular speed and will both >> remain in absolute synch. >> >> The shaft's period can be assigned the value ONE at both top and bottom. >> >> If a clock is sent from the bottom to the top and emits a different number of >> ticks per shaft rotation at each location, then the clock has obviously >> suffered some kind of physical change as a consequence of being moved. The >> shaft period certainly didn't change just because a clock was sent from one end >> to the other. > >Why is that obvious, Henri? >Why do you find it impossible that the shaft simply IS rotating >at a different rotational frequency at different heights? >It doesn't help that YOU call one rotation "one time unit", >if the lengths of those "time units" are different when >measured by local clocks, does it? It depends on how difficult you want life to be. You can either take the simple attitude that "the period of Jupiter represents a constant duration of time " or you can become quite absurd and claim that "it changes depending on how it is measured", ....whether you use a cesium clock or an egg timer.. You people seem obsessed with measurement. Don't you inderstand that the universe functioned perfectly well before human eyes even evolved? Time exists without human life. Jupiter rotated well before the Earth cooled. Its rotation period has occupied a fairly constant length of time ever since. It can be used safely as an 'absolute' time standard. So let's just define it as ONE TIME UNIT. >The only kind of "time" of interest in physics is the "time" >that have physical consequences, and determines the pace of >local physical processes such as clocks. The definition of Jupiter's period as ONE TIME UNIT has EXTREME PHYSICAL SIGNIFICANCE. > > >Paul HW. www.users.bigpond.com/hewn/index.htm Sometimes I feel like a complete failure. The most useful thing I have ever done is prove Einstein wrong.
From: Jeff Root on 22 Aug 2005 19:27 Henri Wilson replied to Jeff Root: > >> Jim has every right to assume that most contributors to this > >> NG have some kind of intelligence which enables them to > >> occasionally apply their own deductive powers in cases when > >> every minute detail is not spelled out as though for a 2yo > >> kid.. > > > > Sure. But it still isn't clear what he meant by "two clocks", > > or how those two clocks are connected to the axle. George > > guessed that each of the two clocks has its own motor or other > > mechanism to make it run, since that is what makes them clocks. > > I, on the other hand, guess that Jim was talking about clock > > hands at each end of the axle, being driven by the rotation > > of the axle, which is, in turn, driven at its bottom end. > > > > George's guess may be right, or mine, or maybe both are wrong > > and Jim's concept is something else. Only Jim can say. > > If you have been following my discussion with George Dishman, you > would know what Jim and I mean. > > The rotation of the shaft itself can be used as a fixed time > duration reference. That was my guess of what Jim was trying to say. The rotating shaft, or axle, serves as a clock. However, when I suggested that to him, he replied that there are definitely two clocks: one at the bottom of the axle and one at the top. So it isn't clear what he really meant. > Its period doesn't need to be measured by any clocks. It can > be assigned the value of ONE time unit. If each of its ends is > connected to a rotating 'hand', the two hands must always be > rotating at the same angular speed and will both remain in > absolute synch. I agree, given certain certain restrictions on exactly what you mean by "angular speed" and "synch". The simplest way to do it would be for the 'hands' to just be marks on the side of the rotating axle-- or just a stripe running up and down the side of the axle. An ideal observer at the bottom would see the stripe twisted slightly by the time delay of the light from more distant parts of the axle taking longer to reach him, as Jim pointed out to me, but of course that twist is constant when the axle is rotating at constant speed, and it is only a simple illusion, not an actual twist in the axle. It isn't the effect you and Jim are interested in. Given that situation, the stripe will actually always be exactly straight up and down. The top end of the stripe will always be directly above the bottom end. Although an observer at the bottom will see the top end lagging behind slightly, and an observer at the top end will see the bottom lagging behind slightly. An observer at the middle will see both ends lagging behind slightly. > The shaft's period can be assigned the value ONE at both top > and bottom. Again I agree, with certain restrictions. The restrictions happen to be crucial to understanding what is going on, but I'm going to put off discussing them until we are sure we agree on the more basic aspects. > If a clock is sent from the bottom to the top and emits a > different number of ticks per shaft rotation at each location, > then the clock has obviously suffered some kind of physical > change as a consequence of being moved. The shaft period > certainly didn't change just because a clock was sent from one > end to the other. Okay. Your version of the thought experiment has two separate 'clocks': one is the huge, rotating axle, turning at a constant rate; the other is portable, ticking at a constant rate. I agree that moving a clock or an observer from one place to another has no effect on the period of the rotating axle. It seems awfully silly to say that it does. Sometimes when people say things that sound silly, or ridiculous, it is because they are speaking in their own dialect, and not yours. You might both think you are speaking the same language, and not even realize that you are using two different dialects, each with its own set of meanings. So what someone says in his own dialect can make perfect sense in that dialect, and sound like nonsense in the other. I'm attempting to communicate with you in your dialect. I agree that moving from place to place has no effect on the axle. That isn't much, but it is something we can agree on. Moving the portable clock also has no effect on the period of that clock. It continues to keep perfect time. It is an ideal clock, made by Santa Claus under God's direct supervision, so it keeps perfect time nomatter what happens to it or what kind of environment it is in. Heat and cold, electric fields, magnetic fields, high g forces-- nothing affects the perfect accuracy of this clock. Actually, the best real clocks come very, very close to that ideal. They are tested under all kinds of extreme conditions, and if any variation is detected, the design is changed so the condition no longer causes any variation. The testing never stops, either. The clocks continue to be carefully tested years after they've been made. They are used every day for all kinds of precision measurements, positioning, and finding exact locations of things, often to within a few inches, all around the world. So it is very important that they be both accurate and precise, to do the jobs they're used for. You suggested above that the portable clock might tick some number of times per shaft rotation when at the bottom of the shaft, and a different number of times per shaft rotation when at the top of the shaft. I'm going to ask you: What makes you think that the clock might tick a different number of times per shaft rotation depending on where it is? -- Jeff, in Minneapolis
From: Henri Wilson on 23 Aug 2005 17:50
On 22 Aug 2005 16:27:40 -0700, "Jeff Root" <jeff5(a)freemars.org> wrote: >Henri Wilson replied to Jeff Root: > >> >> Jim has every right to assume that most contributors to this >> >> NG have some kind of intelligence which enables them to >> >> occasionally apply their own deductive powers in cases when >> >> every minute detail is not spelled out as though for a 2yo >> >> kid.. >> > >> > Sure. But it still isn't clear what he meant by "two clocks", >> > or how those two clocks are connected to the axle. George >> > guessed that each of the two clocks has its own motor or other >> > mechanism to make it run, since that is what makes them clocks. >> > I, on the other hand, guess that Jim was talking about clock >> > hands at each end of the axle, being driven by the rotation >> > of the axle, which is, in turn, driven at its bottom end. >> > >> > George's guess may be right, or mine, or maybe both are wrong >> > and Jim's concept is something else. Only Jim can say. >> >> If you have been following my discussion with George Dishman, you >> would know what Jim and I mean. >> >> The rotation of the shaft itself can be used as a fixed time >> duration reference. > >That was my guess of what Jim was trying to say. The rotating >shaft, or axle, serves as a clock. However, when I suggested >that to him, he replied that there are definitely two clocks: >one at the bottom of the axle and one at the top. So it isn't >clear what he really meant. > >> Its period doesn't need to be measured by any clocks. It can >> be assigned the value of ONE time unit. If each of its ends is >> connected to a rotating 'hand', the two hands must always be >> rotating at the same angular speed and will both remain in >> absolute synch. > >I agree, given certain certain restrictions on exactly what >you mean by "angular speed" and "synch". The simplest way to >do it would be for the 'hands' to just be marks on the side of >the rotating axle-- or just a stripe running up and down the >side of the axle. An ideal observer at the bottom would see >the stripe twisted slightly by the time delay of the light >from more distant parts of the axle taking longer to reach him, >as Jim pointed out to me, but of course that twist is constant >when the axle is rotating at constant speed, and it is only a >simple illusion, not an actual twist in the axle. It isn't >the effect you and Jim are interested in. > >Given that situation, the stripe will actually always be >exactly straight up and down. The top end of the stripe will >always be directly above the bottom end. Although an observer >at the bottom will see the top end lagging behind slightly, >and an observer at the top end will see the bottom lagging >behind slightly. An observer at the middle will see both ends >lagging behind slightly. > >> The shaft's period can be assigned the value ONE at both top >> and bottom. > >Again I agree, with certain restrictions. The restrictions >happen to be crucial to understanding what is going on, but >I'm going to put off discussing them until we are sure we >agree on the more basic aspects. > >> If a clock is sent from the bottom to the top and emits a >> different number of ticks per shaft rotation at each location, >> then the clock has obviously suffered some kind of physical >> change as a consequence of being moved. The shaft period >> certainly didn't change just because a clock was sent from one >> end to the other. > >Okay. Your version of the thought experiment has two separate >'clocks': one is the huge, rotating axle, turning at a constant >rate; the other is portable, ticking at a constant rate. > >I agree that moving a clock or an observer from one place to >another has no effect on the period of the rotating axle. >It seems awfully silly to say that it does. Sometimes when >people say things that sound silly, or ridiculous, it is >because they are speaking in their own dialect, and not yours. >You might both think you are speaking the same language, and >not even realize that you are using two different dialects, >each with its own set of meanings. So what someone says in >his own dialect can make perfect sense in that dialect, and >sound like nonsense in the other. > >I'm attempting to communicate with you in your dialect. > >I agree that moving from place to place has no effect on the >axle. That isn't much, but it is something we can agree on. > >Moving the portable clock also has no effect on the period of >that clock. It continues to keep perfect time. It is an ideal >clock, made by Santa Claus under God's direct supervision, so >it keeps perfect time nomatter what happens to it or what kind >of environment it is in. Heat and cold, electric fields, >magnetic fields, high g forces-- nothing affects the perfect >accuracy of this clock. > >Actually, the best real clocks come very, very close to that >ideal. They are tested under all kinds of extreme conditions, >and if any variation is detected, the design is changed so the >condition no longer causes any variation. The testing never >stops, either. The clocks continue to be carefully tested >years after they've been made. They are used every day for >all kinds of precision measurements, positioning, and finding >exact locations of things, often to within a few inches, all >around the world. So it is very important that they be both >accurate and precise, to do the jobs they're used for. > >You suggested above that the portable clock might tick some >number of times per shaft rotation when at the bottom of the >shaft, and a different number of times per shaft rotation when >at the top of the shaft. I'm going to ask you: > >What makes you think that the clock might tick a different >number of times per shaft rotation depending on where it is? A perfect clock should not change its rate no matter what happens to it.. Real clocks as used in the GPS system DO speed up slightly when placed in free fall. I am merely accepting observed facts. I suggest that there are several reasons for the change in GPS clocks ...and none involves GR. > > -- Jeff, in Minneapolis HW. www.users.bigpond.com/hewn/index.htm Sometimes I feel like a complete failure. The most useful thing I have ever done is prove Einstein wrong. |