Ballistic Theory, Progress report...Suitable for 5yo Kids
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From: Paul B. Andersen on 25 Aug 2005 04:34 Henri Wilson wrote: > On Wed, 24 Aug 2005 09:55:36 +0200, "Paul B. Andersen" > <paul.b.andersen(a)deletethishia.no> wrote: > > >>Henri Wilson wrote: >> >>>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. >> >>To Jupiter. >>But it is of no use if you want to boil your eggs. >>Then you will have to use a local clock running with >>the pace governed by the same laws of physics which >>determine the coagulation of your egg. > > > Do you agree that the ratio of Jupiter's rotation to Earth's rotation is > constant and independent of measuring frame? No. Paul
From: jgreen on 25 Aug 2005 06:10 George Dishman wrote: > <jgreen(a)seol.net.au> wrote in message > news:1124864703.213704.5830(a)g14g2000cwa.googlegroups.com... > ... > > (attn George) > > Once the axle is spinning, let it rotate on frictionless bearings, with > > very energy efficient clocks (or one with hands at each end of the > > axle, if you prefer). No motors now driving- why a twisting? > > No motors, no twist. > > Jim this is really easy. Think for a moment about > a horizontal shaft to take GR out of the picture. > If it has frictionless bearings and you start it > spinning, it will continue to spin at that rate. > Attach one end to a motor that rotates once every > second and the shaft will rotate with the motor. > Now attach the other end to a second motor that > rotates twice per second. The shaft gets twisted > and the power must come from the motors. That > should be trivial so far. > > Now let's consider the vertical shaft. Attach a > motor at the bottom and place a perfect clock > next to it. Adjust the motor so it that rotates > once per second as measured by that motor. Now > place a second identical perfect clock at the top. > By that clock, the shaft takes a little more than > a second to rotate. If you attach a second motor > that rotates once per second according to the top > clock, the shaft gets twisted and again the power > simply comes from the motors. No "If" George! Why introduce a second motor? Actually, NO motors are required unless you wish to introduce the history of what happened BEFORE the axle began its constant rotation (at ground). A clock at ground is ticking away, and at the same time counting the revs (frequency); another at the top is doing the same, and I maintain that for the two results to be the same under GR: 1) The clocks do NOT tick together 2) A twisting must be occuring (It would be pretty cool, if the earth's internal heat was actually caused by this effect- an energy process driven by the gravitationally induced "time difference" between the surface and core {grav gradient}) > > This is only surprising if you make the assumption > that time is universal hence if the bottom clock > reads 1s per turn so should the top clock. ......and if you accept that time can be of any duration which suits (AE), then magic of SR/GR trumps logic. (Book of Prophets 12/55) Cheers Jim G c'=c+v PS: Light measured at differring speeds in fibres George! Problems for Sagnac analysis (reason for ot working)
From: George Dishman on 25 Aug 2005 07:09 <jgreen(a)seol.net.au> wrote in message news:1124964627.644118.142680(a)o13g2000cwo.googlegroups.com... > > George Dishman wrote: >> <jgreen(a)seol.net.au> wrote in message >> news:1124864703.213704.5830(a)g14g2000cwa.googlegroups.com... >> ... >> > (attn George) >> > Once the axle is spinning, let it rotate on frictionless bearings, with >> > very energy efficient clocks (or one with hands at each end of the >> > axle, if you prefer). No motors now driving- why a twisting? >> >> No motors, no twist. >> >> Jim this is really easy. Think for a moment about >> a horizontal shaft to take GR out of the picture. >> If it has frictionless bearings and you start it >> spinning, it will continue to spin at that rate. >> Attach one end to a motor that rotates once every >> second and the shaft will rotate with the motor. >> Now attach the other end to a second motor that >> rotates twice per second. The shaft gets twisted >> and the power must come from the motors. That >> should be trivial so far. >> >> Now let's consider the vertical shaft. Attach a >> motor at the bottom and place a perfect clock >> next to it. Adjust the motor so it that rotates >> once per second as measured by that motor. Now >> place a second identical perfect clock at the top. >> By that clock, the shaft takes a little more than >> a second to rotate. If you attach a second motor >> that rotates once per second according to the top >> clock, the shaft gets twisted and again the power >> simply comes from the motors. > > No "If" George! > Why introduce a second motor? Because you asked about what would cause a twist - no motors, no twist. I think Jeff is right, you need to sit quietly for a while and think through what you are trying to ask. > Actually, NO motors are required > unless you wish to introduce the history of what happened BEFORE the > axle began its constant rotation (at ground). If there are no motors, there is nothing to produce the torque to twist the shaft. > A clock at ground is ticking away, and at the same time counting the > revs (frequency); another at the top is doing the same, and I maintain > that for the two results to be the same under GR: Bzzzt, error. Under GR, the measured rates will be different and in real life we know they are. > PS: Light measured at differring speeds in fibres George! Problems for > Sagnac analysis (reason for ot working) The light is sent both ways round the same fibre so refractive index affects the speed of each beam equally. Try again. George
From: Jeff Root on 25 Aug 2005 16:34 Jim Greenfield replied to George Dishman: >> > (attn George) >> > Once the axle is spinning, let it rotate on frictionless >> > bearings, with very energy efficient clocks (or one with >> > hands at each end of the axle, if you prefer). No motors >> > now driving- why a twisting? >> >> No motors, no twist. >> >> Jim this is really easy. Think for a moment about >> a horizontal shaft to take GR out of the picture. >> If it has frictionless bearings and you start it >> spinning, it will continue to spin at that rate. >> Attach one end to a motor that rotates once every >> second and the shaft will rotate with the motor. >> Now attach the other end to a second motor that >> rotates twice per second. The shaft gets twisted >> and the power must come from the motors. That >> should be trivial so far. >> >> Now let's consider the vertical shaft. Attach a >> motor at the bottom and place a perfect clock >> next to it. Adjust the motor so it that rotates >> once per second as measured by that motor. Now >> place a second identical perfect clock at the top. >> By that clock, the shaft takes a little more than >> a second to rotate. If you attach a second motor >> that rotates once per second according to the top >> clock, the shaft gets twisted and again the power >> simply comes from the motors. > > No "If" George! > Why introduce a second motor? He obviously introduced it to provide a way to get the twisting effect you're looking for. Without two separate sources of torque, the axle will not twist. He was just showing a situation where the axle *will* twist, even though it doesn't tell us anything about relativity. > Actually, NO motors are required unless you wish to > introduce the history of what happened BEFORE the > axle began its constant rotation (at ground). I agree completely with that. Either one motor or none works fine for this thought experiment. > A clock at ground is ticking away, and at the same time > counting the revs (frequency); Those are two separate functions: a clock and a counter, but that isn't a problem. Okay. > another at the top is doing the same, and I maintain > that for the two results to be the same under GR: > 1) The clocks do NOT tick together That is what GR predicts and measurements show. > 2) A twisting must be occuring Why? Nobody predicts that but you. GR certainly doesn't. No effects equivalent to such a twisting have been observed. Why do you predict a twisting? > (It would be pretty cool, if the earth's internal heat was > actually caused by this effect- an energy process driven > by the gravitationally induced "time difference" between > the surface and core {grav gradient}) Since there is no effect, it can't cause anything. :-) >> This is only surprising if you make the assumption >> that time is universal hence if the bottom clock >> reads 1s per turn so should the top clock. > > .....and if you accept that time can be of any duration What do you mean by the phrase 'time can be of any duration'? -- Jeff, in Minneapolis
From: Henri Wilson on 25 Aug 2005 18:32
On Thu, 25 Aug 2005 10:34:27 +0200, "Paul B. Andersen" <paul.b.andersen(a)deletethishia.no> wrote: >Henri Wilson wrote: >> On Wed, 24 Aug 2005 09:55:36 +0200, "Paul B. Andersen" >> <paul.b.andersen(a)deletethishia.no> wrote: >> >> >>>To Jupiter. >>>But it is of no use if you want to boil your eggs. >>>Then you will have to use a local clock running with >>>the pace governed by the same laws of physics which >>>determine the coagulation of your egg. >> >> >> Do you agree that the ratio of Jupiter's rotation to Earth's rotation is >> constant and independent of measuring frame? > >No. Therein lies your problem. > >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. |