The moving system is not an inertial frame in 1905 Relativity
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From: valls on 30 Jun 2010 16:03 In a recent thread we established that Centre of mass inertial frames are the unique ones in 1905 Relativity http://groups.google.com.cu/group/sci.physics.relativity/browse_frm/thread/0c8501991104d36c?hl=es# We cant have two (or more) of them at the same time, because the bodies belonging to all of them determine a unique centre of mass inertial frame. As a result, in 1905 Relativity the moving system (MS) can be only a body (or subset) belonging to the body set of the unique inertial frame (the stationary system). The MS can be moving with any velocity compatible with the same laws valid in every inertial frame, not being then in general an inertial one. See the example at the end of paragraph 4 of the 30Jun1905 Einsteins paper (rotating Earth).
From: Daryl McCullough on 30 Jun 2010 16:13 valls(a)icmf.inf.cu says... > >In a recent thread we established that > Centre of mass inertial frames are the unique ones in 1905 >Relativity There is nothing in the development of relativity that in any way depends on a frame being defined by a center of mass. That's completely barking up the wrong tree. -- Daryl McCullough Ithaca, NY
From: valls on 30 Jun 2010 16:31 On 30 jun, 15:13, stevendaryl3...(a)yahoo.com (Daryl McCullough) wrote: > va...(a)icmf.inf.cu says... > > > > >In a recent thread we established that > > Centre of mass inertial frames are the unique ones in 1905 > >Relativity > > There is nothing in the development of relativity that in any > way depends on a frame being defined by a center of mass. That's > completely barking up the wrong tree. > > -- > Daryl McCullough > Ithaca, NY I will answer you with the same initial post of the referred thread: [Let be any body set with a material point modelling each one. If we want to describe the movements of the bodies in an inertial frame, we have a unique alternative: to use the centre of mass inertial frame corresponding to that body set. Once the Newtons absolute frame is rejected by 1905 Einstein (and then rejected also all the others moving with any uniform velocity with respect to it), remain only the bodies themselves to determine inertial frames.] Explain to us how can you determine an inertial frame once the absolute Newtonian one is rejected by 1905 Einstein(and with it all the others imaginary derived ones with all possible uniform velocities with respect to it). RVHG (Rafael Valls Hidalgo-Gato)
From: BURT on 30 Jun 2010 17:36 On Jun 30, 1:31 pm, va...(a)icmf.inf.cu wrote: > On 30 jun, 15:13, stevendaryl3...(a)yahoo.com (Daryl McCullough) wrote: > > > va...(a)icmf.inf.cu says... > > > >In a recent thread we established that > > > Centre of mass inertial frames are the unique ones in 1905 > > >Relativity > > > There is nothing in the development of relativity that in any > > way depends on a frame being defined by a center of mass. That's > > completely barking up the wrong tree. > > > -- > > Daryl McCullough > > Ithaca, NY > > I will answer you with the same initial post of the referred thread: > [Let be any body set with a material point modelling each one. If we > want to describe the movements of the bodies in an inertial frame, we > have a unique alternative: to use the centre of mass inertial frame > corresponding to that body set. Once the Newtons absolute frame is > rejected by 1905 Einstein (and then rejected also all the others > moving with any uniform velocity with respect to it), remain only the > bodies themselves to determine inertial frames.] > Explain to us how can you determine an inertial frame once the > absolute Newtonian one is rejected by 1905 Einstein(and with it all > the others imaginary derived ones with all possible uniform velocities > with respect to it). > > RVHG (Rafael Valls Hidalgo-Gato) If something begins to move and is weighted it sees an opposite motion of things around it with the weight in that direction. When the Earth turns the Sun crosses the sky in the opposite direction. This is relative motion. And weight for motion is resistance to change in motion. Mitch Raemsch
From: Daryl McCullough on 30 Jun 2010 17:38
valls(a)icmf.inf.cu says... >Explain to us how can you determine an inertial frame once the >absolute Newtonian one is rejected by 1905 Einstein(and with it all >the others imaginary derived ones with all possible uniform velocities >with respect to it). First of all, you need to be able to distinguish constant velocity motion from accelerated motion. There are several different ways of doing this. One way is to use an accelerometer. Basically, an accelerometer is just a mass on a spring. If the spring is in its equilibrium position, then the accelerometer is not accelerating (at least not in the direction of the length of the spring). Another alternative approach is to set up a coordinate system inside a closed box by partitioning the box up into identical tiny cubes. If the box is not accelerating, then light will travel in straight lines relative to the box's coordinate system. Otherwise, it will travel along a curved path. The third approach is just to use the fact that an object will not accelerate unless it is acted upon by an external force. If you have eliminated all known forces acting on the objects, then it's a good bet that they will be unaccelerated. So if you can determine that an object is unaccelerated, then you can set up an inertial coordinate system as follows: (for simplicity, let's just discuss a single dimension, the x-axis) Get a collection of many identical clocks. Move them until they are spread out in a straight line. (You can tell that it is a straight line because light travels in straight lines). Make sure that all clocks are traveling along unaccelerated paths. Pick one clock to be your reference, and then make sure that all other clocks are at rest relative to this clock. How do you do that? Well, you can use light signals to measure the distances between clocks: send a light signal from one clock to the other and then back to the first. Measure the time required for a round trip. Do this a second time. If both clocks are unaccelerated, and you do this measurement twice, and you get the same answer both times, then the clocks are at rest relative to one another. You adjust the speeds of all clocks until they are at rest relative to the reference clock. To compute the distances between clocks, you just use the formula: cT = 2D where D is the distance between clocks at rest relative to one another, T is the round-trip time for a light signal, and c is the speed of light. Now, you have to synchronize the clocks. You do this using light signals again. When the reference clock shows time t_1, send a light signal towards another clock. When the light signal reaches the second clock, set that clock to time t_1 + D/c, where D is the distance between that clock and the reference clock, computed earlier. Do this to synchronize all the clocks with respect to the reference clock. After synchronizing, we have a coordinate system: For any event e, you compute the coordinates of e as follows: x = the distance from the reference clock to the closest clock to event e. t = the time shown on that clock when e occurs. This of course only gives coordinates approximately, so you have to interpolate to get more fine-grained coordinates associated with events. -- Daryl McCullough Ithaca, NY |