SR and a lightbulb
in [Relativity]
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From: eric gisse on 7 Jan 2010 18:13 ...@..(Henry Wilson DSc) wrote: > On Thu, 7 Jan 2010 12:55:33 -0800 (PST), PD <thedraperfamily(a)gmail.com> > wrote: > >>On Jan 7, 2:41 pm, ..@..(Henry Wilson DSc) wrote: >>> On Thu, 7 Jan 2010 06:54:28 -0800 (PST), PD <thedraperfam...(a)gmail.com> >>> wrote: >>> >On Jan 6, 6:29 pm, ..@..(Henry Wilson DSc) wrote: > >>> >This has nothing to do with what humans see. This is a matter of >>> >whether the barn door strikes the pole or not, which can be recorded >>> >with or without humans present. >>> >>> >Now: At the time when the front of the pole hits the back wall of the >>> >barn, what happens to the back end of the pole AT THAT INSTANT? >>> >>> At any particular instant...or if time diesn't even exist ...the two >>> ends of the pole are separated by the same absolute spatial interval. >> >>I'll be a little more precise: At the instant when the motion of the >>front of the pole stops as it hits the back wall of the barn, what >>happens to the motion of the back of the pole? > > It stops instantly as well. Reality doesn't rely on what humans see. Really? Instantly? [...]
From: Inertial on 7 Jan 2010 18:22 "eric gisse" <jowr.pi.nospam(a)gmail.com> wrote in message news:hi5pqa$ibd$2(a)news.eternal-september.org... > ..@..(Henry Wilson DSc) wrote: > >> On Thu, 7 Jan 2010 12:55:33 -0800 (PST), PD <thedraperfamily(a)gmail.com> >> wrote: >> >>>On Jan 7, 2:41 pm, ..@..(Henry Wilson DSc) wrote: >>>> On Thu, 7 Jan 2010 06:54:28 -0800 (PST), PD <thedraperfam...(a)gmail.com> >>>> wrote: >>>> >On Jan 6, 6:29 pm, ..@..(Henry Wilson DSc) wrote: >> >>>> >This has nothing to do with what humans see. This is a matter of >>>> >whether the barn door strikes the pole or not, which can be recorded >>>> >with or without humans present. >>>> >>>> >Now: At the time when the front of the pole hits the back wall of the >>>> >barn, what happens to the back end of the pole AT THAT INSTANT? >>>> >>>> At any particular instant...or if time diesn't even exist ...the two >>>> ends of the pole are separated by the same absolute spatial interval. >>> >>>I'll be a little more precise: At the instant when the motion of the >>>front of the pole stops as it hits the back wall of the barn, what >>>happens to the motion of the back of the pole? >> >> It stops instantly as well. Reality doesn't rely on what humans see. > > Really? Instantly? We all know it .. Henry just has no idea of physics. Why does he just keep on showing us his ignorance of it over and over. "It is better to keep your mouth closed and let people think you are a fool than to open it and remove all doubt." -- Mark Twain
From: train on 7 Jan 2010 18:53 On Jan 8, 4:22 am, "Inertial" <relativ...(a)rest.com> wrote: > "eric gisse" <jowr.pi.nos...(a)gmail.com> wrote in message > > news:hi5pqa$ibd$2(a)news.eternal-september.org... > > > > > > > ..@..(Henry Wilson DSc) wrote: > > >> On Thu, 7 Jan 2010 12:55:33 -0800 (PST), PD <thedraperfam...(a)gmail.com> > >> wrote: > > >>>On Jan 7, 2:41 pm, ..@..(Henry Wilson DSc) wrote: > >>>> On Thu, 7 Jan 2010 06:54:28 -0800 (PST), PD <thedraperfam...(a)gmail.com> > >>>> wrote: > >>>> >On Jan 6, 6:29 pm, ..@..(Henry Wilson DSc) wrote: > > >>>> >This has nothing to do with what humans see. This is a matter of > >>>> >whether the barn door strikes the pole or not, which can be recorded > >>>> >with or without humans present. > > >>>> >Now: At the time when the front of the pole hits the back wall of the > >>>> >barn, what happens to the back end of the pole AT THAT INSTANT? > > >>>> At any particular instant...or if time diesn't even exist ...the two > >>>> ends of the pole are separated by the same absolute spatial interval.. > > >>>I'll be a little more precise: At the instant when the motion of the > >>>front of the pole stops as it hits the back wall of the barn, what > >>>happens to the motion of the back of the pole? > > >> It stops instantly as well. Reality doesn't rely on what humans see. > > > Really? Instantly? > > We all know it .. Henry just has no idea of physics. Why does he just keep > on showing us his ignorance of it over and over. > > "It is better to keep your mouth closed and let people think you are a fool > than to open it and remove all doubt." -- Mark Twain So better not keep your mouth open when sending emails, Henry
From: train on 7 Jan 2010 19:01 On Jan 8, 4:13 am, eric gisse <jowr.pi.nos...(a)gmail.com> wrote: > ..@..(Henry Wilson DSc) wrote: > > On Thu, 7 Jan 2010 12:55:33 -0800 (PST), PD <thedraperfam...(a)gmail.com> > > wrote: > > >>On Jan 7, 2:41 pm, ..@..(Henry Wilson DSc) wrote: > >>> On Thu, 7 Jan 2010 06:54:28 -0800 (PST), PD <thedraperfam...(a)gmail.com> > >>> wrote: > >>> >On Jan 6, 6:29 pm, ..@..(Henry Wilson DSc) wrote: > > >>> >This has nothing to do with what humans see. This is a matter of > >>> >whether the barn door strikes the pole or not, which can be recorded > >>> >with or without humans present. > > >>> >Now: At the time when the front of the pole hits the back wall of the > >>> >barn, what happens to the back end of the pole AT THAT INSTANT? > > >>> At any particular instant...or if time diesn't even exist ...the two > >>> ends of the pole are separated by the same absolute spatial interval. > > >>I'll be a little more precise: At the instant when the motion of the > >>front of the pole stops as it hits the back wall of the barn, what > >>happens to the motion of the back of the pole? > > > It stops instantly as well. Reality doesn't rely on what humans see. > > Really? Instantly? > > [...] We this is indeed the point. Can anything travel faster than light? When the pole hits the back of the barn door and stops instantly, the impact has to be transmitted through the pole atom by atom. Can this happen faster than the speed of light? In classical mechanics yes In SRT if you follow it, you will have two effects The instant the pole stops, the length contraction disappears, atom by atom along the length of the pole, at the speed of light. as the stopping of the pole also takes place at the speed of light atom by atom. The pole will then pop right out of the front of the Barn Door. All this for the farmer watching the pole fly through the barn door at close to the speed of light.
From: Darwin123 on 7 Jan 2010 19:35
On Dec 29 2009, 10:17 pm, dlzc <dl...(a)cox.net> wrote: > On Dec 29, 7:46 pm, dk <dakalami...(a)sci.ccny.cuny.edu> wrote: > > > I should have mentioned that it is assumed > > that the wires on the lightbulb device are > > insulated and only at their endpoints is the > > conductor exposed so as to make contact with > > x1 and x2 in frame S. > > Draw a diagram. How are the wires oriented wrt the x axis? > > Next, wires have inductance. Only in a fantasy world does the light > "flash". I would like to add: "Wires have an inductance. therefore the signal traveling from switch to light bulb has to move slower than the speed of light. you have to include the propagation time of the electric power once the circuit is complete. Most of the signal upon completing the circuit will actually move slower than the speed of light. Plus the fact that the filament needs time to heat. To facilitate the discussion, assume that the signal moves from switch to light bulb at the speed of light, and that the light bulb heats up "instantly." Also include the propagation time of the light from bulb to observers." > > David A. Smith |