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# If i shine a torch out of a train

 Posts: 1,420 Add as FriendChallenge to a DebateSend a Message 1/2/2014 6:41:48 PMPosted: 4 years agomoving at 100m/s^2 why doesn't it move at 300,000m/s^2+100m/s^2?
 Posts: 1,420 Add as FriendChallenge to a DebateSend a Message 1/2/2014 6:42:31 PMPosted: 4 years agoWhy doesn't the light from it move at 300,000m/s^2+100m/s^2, I mean.
 Posts: 751 Add as FriendChallenge to a DebateSend a Message 1/3/2014 6:20:49 AMPosted: 4 years agoAt 1/2/2014 6:42:31 PM, Installgentoo wrote:Why doesn't the light from it move at 300,000m/s^2+100m/s^2, I mean.Because the speed of light (in a vacuum) is constant.
 Posts: 20 Add as FriendChallenge to a DebateSend a Message 1/5/2014 4:42:11 PMPosted: 4 years agoBecause the relative distance and time would have changed slightly to allow light to remain constant. The faster something moves, the shorter it gets in the direction of travel, and the faster time moves for it.Religion is the impotence of the human mind to deal with occurrences it cannot understand (Karl Marx).
 Posts: 294 Add as FriendChallenge to a DebateSend a Message 1/5/2014 5:03:19 PMPosted: 4 years agoAt 1/3/2014 6:20:49 AM, Floid wrote:At 1/2/2014 6:42:31 PM, Installgentoo wrote:Why doesn't the light from it move at 300,000m/s^2+100m/s^2, I mean.Because the speed of light (in a vacuum) is constant.This is not really an answer.Why is it supposedly constant in vacuum?
 Posts: 5,466 Add as FriendChallenge to a DebateSend a Message 1/5/2014 5:18:45 PMPosted: 4 years agoAt 1/2/2014 6:41:48 PM, Installgentoo wrote:moving at 100m/s^2 why doesn't it move at 300,000m/s^2+100m/s^2?One answer is that m/s^2 is acceleration and not speed, but I'm assuming that's not what you meant.It does. Sort of.If we assume you are shining it out of the front of the train and you somehow measure it, you will measure it as travelling at 300km/s, if you know you're travelling at 100m/s (224mph), that will work out as 300.1km/s.However if you're travelling at this speed, time slows down very slightly (and distance gets a little shorter), so that while you measure it as 300.1km/s, someone else that is standing still compared to you will measure it as 300km/s.It's all down to relative speeds of observers. Remember the train isn't moving at 100m/s, it is moving 100m/s plus the contribution of the rotation of the earth, and the orbit of the earth around the sun, and the sun around the galactive centre, and the relative motion of the galaxy to other galaxies.
 Posts: 3,781 Add as FriendChallenge to a DebateSend a Message 1/5/2014 5:34:44 PMPosted: 4 years agoAt 1/5/2014 5:18:45 PM, Ramshutu wrote:At 1/2/2014 6:41:48 PM, Installgentoo wrote:moving at 100m/s^2 why doesn't it move at 300,000m/s^2+100m/s^2?One answer is that m/s^2 is acceleration and not speed, but I'm assuming that's not what you meant.It does. Sort of.If we assume you are shining it out of the front of the train and you somehow measure it, you will measure it as travelling at 300km/s, if you know you're travelling at 100m/s (224mph), that will work out as 300.1km/s.However if you're travelling at this speed, time slows down very slightly (and distance gets a little shorter), so that while you measure it as 300.1km/s, someone else that is standing still compared to you will measure it as 300km/s.It's all down to relative speeds of observers. Remember the train isn't moving at 100m/s, it is moving 100m/s plus the contribution of the rotation of the earth, and the orbit of the earth around the sun, and the sun around the galactive centre, and the relative motion of the galaxy to other galaxies.Deep.bladerunner060 | bsh1 , 2014! Presidency campaign! http://www.debate.org... http://www.debate.org... - Running for president. http://www.debate.org... - Running as his vice president. May the best man win!
 Posts: 561 Add as FriendChallenge to a DebateSend a Message 1/6/2014 5:23:46 AMPosted: 4 years agoAt 1/2/2014 6:41:48 PM, Installgentoo wrote:moving at 100m/s^2 why doesn't it move at 300,000m/s^2+100m/s^2?(Btw Speed of light is 300,000,000 ms^-1.)What do you mean by "moving at 100ms^-1" ? How are you measuring your speed? How will you measure the speed of light?It is a postulate of physics that the laws of physics are independent of velocity. In practical terms what this means is that none of the laws of physics change if you travel at a different steady speed. This leads to the idea that there is no real difference between being moving (at a steady speed) and being stationary.So when you say "moving at 100ms^-1" that is the same as saying things are moving past me at 100ms^-1. Would you expect the speed of light to change just because something moves past you? Obviously not.The speed of light can be derived from Maxwell's laws of electromagnetism. Basically this means that the speed of light is as fixed as the laws of physics.You are essentially asking "Why are the laws of physics fixed?" I don't think anyone knows an answer to that.An observer who moves past you at 100 ms^-1 might be expected to see the light move at 300,000,000 ms^-1 + 100 ms^-1 but experiment has shown that this is not the case. For a detailed explanation of how two moving observers can measure the same light pulse move relative to themselves at 300,000,000 ms^-1 when they are moving relative to each other requires special relativity theory. Essentially this says that measurement of time and distance are not absolute but depend on relative speed eg a moving clock runs slower than a stationary clock.Let's hope "the truth is out there" cos there is bugger all round here.
 Posts: 561 Add as FriendChallenge to a DebateSend a Message 1/6/2014 6:28:31 AMPosted: 4 years agoAt 1/5/2014 5:18:45 PM, Ramshutu wrote:At 1/2/2014 6:41:48 PM, Installgentoo wrote:moving at 100m/s^2 why doesn't it move at 300,000m/s^2+100m/s^2?It does. Sort of.If we assume you are shining it out of the front of the train and you somehow measure it, ....This is an important point. How do we measure speed.....you will measure it as travelling at 300Mm/s, if you know you're travelling at 100m/s (224mph), that will work out as 300.001Mm/s.This is an inference that cannot be directly measured.However if you're travelling at this speed, time slows down very slightly (and distance gets a little shorter),...Only an external observer would see a change in time and distance. For you time and space do not change....so that while you measure it as 300.001Mm/s,You mean this is an inferred speed of light relative to objects moving relative to you. The direct measurement will be the speed of light.someone else that is standing still compared to you will measure it as 300Mm/s.Relative to themselves.It's all down to relative speeds of observers. Remember the train isn't moving at 100m/s, it is moving 100m/s plus the contribution of the rotation of the earth, and the orbit of the earth around the sun, and the sun around the galactive centre, and the relative motion of the galaxy to other galaxies.But also in a very real sense the train is stationary.Let's hope "the truth is out there" cos there is bugger all round here.
 Posts: 751 Add as FriendChallenge to a DebateSend a Message 1/6/2014 6:53:57 AMPosted: 4 years agoAt 1/5/2014 5:03:19 PM, nummi wrote:At 1/3/2014 6:20:49 AM, Floid wrote:At 1/2/2014 6:42:31 PM, Installgentoo wrote:Why doesn't the light from it move at 300,000m/s^2+100m/s^2, I mean.Because the speed of light (in a vacuum) is constant.This is not really an answer.Why is it supposedly constant in vacuum?That is the answer. Light moves away at the speed of light because that speed is constant.Why is it constant is a different question. The answer to that question is we don't know.We do know enough to not need to say "supposedly". Science inherently leaves open the possibility of its statements being wrong. We don't have to say "supposedly F = MA" or "supposedly matter is made of atoms". Instead we simply say the speed of light is constant in a vacuum... it is understood that as our knowledge progresses this could change.
 Posts: 5,466 Add as FriendChallenge to a DebateSend a Message 1/6/2014 6:08:30 PMPosted: 4 years agoAt 1/6/2014 6:28:31 AM, chui wrote:At 1/5/2014 5:18:45 PM, Ramshutu wrote:At 1/2/2014 6:41:48 PM, Installgentoo wrote:moving at 100m/s^2 why doesn't it move at 300,000m/s^2+100m/s^2?It does. Sort of.If we assume you are shining it out of the front of the train and you somehow measure it, ....This is an important point. How do we measure speed.The speed of light is pretty easy; you can look at discontinuities in orbits of Io, as Roemer did (and came bloody close), modern day you can measure round trip times with lasers and mirrors.....you will measure it as travelling at 300Mm/s, if you know you're travelling at 100m/s (224mph), that will work out as 300.001Mm/s.This is an inference that cannot be directly measured.Which is why I said sort of.However if you're travelling at this speed, time slows down very slightly (and distance gets a little shorter),...Only an external observer would see a change in time and distance. For you time and space do not change.Well, yes. This is really only a semantic error, though....so that while you measure it as 300.001Mm/s,You mean this is an inferred speed of light relative to objects moving relative to you. The direct measurement will be the speed of light.Yes. Hence the "sort of".someone else that is standing still compared to you will measure it as 300Mm/s.Relative to themselves.Well, yes. This is really only a semantic error, though.It's all down to relative speeds of observers. Remember the train isn't moving at 100m/s, it is moving 100m/s plus the contribution of the rotation of the earth, and the orbit of the earth around the sun, and the sun around the galactive centre, and the relative motion of the galaxy to other galaxies.But also in a very real sense the train is stationary.Well, yes. My main aim here was to try and boil down the complexity of the theory for the originating troll. I could have gone to the pure theoretical relativity (special or general), but I suspect the OP would have lost patience and started trying to pick fleas of me.
 Posts: 561 Add as FriendChallenge to a DebateSend a Message 1/7/2014 3:14:38 AMPosted: 4 years agoAt 1/6/2014 6:08:30 PM, Ramshutu wrote:At 1/6/2014 6:28:31 AM, chui wrote:At 1/5/2014 5:18:45 PM, Ramshutu wrote:At 1/2/2014 6:41:48 PM, Installgentoo wrote:moving at 100m/s^2 why doesn't it move at 300,000m/s^2+100m/s^2?It does. Sort of.If we assume you are shining it out of the front of the train and you somehow measure it, ....This is an important point. How do we measure speed.The speed of light is pretty easy; you can look at discontinuities in orbits of Io, as Roemer did (and came bloody close), modern day you can measure round trip times with lasers and mirrors.....you will measure it as travelling at 300Mm/s, if you know you're travelling at 100m/s (224mph), that will work out as 300.001Mm/s.This is an inference that cannot be directly measured.Which is why I said sort of.However if you're travelling at this speed, time slows down very slightly (and distance gets a little shorter),...Only an external observer would see a change in time and distance. For you time and space do not change.Well, yes. This is really only a semantic error, though....so that while you measure it as 300.001Mm/s,You mean this is an inferred speed of light relative to objects moving relative to you. The direct measurement will be the speed of light.Yes. Hence the "sort of".someone else that is standing still compared to you will measure it as 300Mm/s.Relative to themselves.Well, yes. This is really only a semantic error, though.It's all down to relative speeds of observers. Remember the train isn't moving at 100m/s, it is moving 100m/s plus the contribution of the rotation of the earth, and the orbit of the earth around the sun, and the sun around the galactive centre, and the relative motion of the galaxy to other galaxies.But also in a very real sense the train is stationary.Well, yes. My main aim here was to try and boil down the complexity of the theory for the originating troll. I could have gone to the pure theoretical relativity (special or general), but I suspect the OP would have lost patience and started trying to pick fleas of me.A fair point. In that light I understand your initial post here.Let's hope "the truth is out there" cos there is bugger all round here.
 Posts: 5,466 Add as FriendChallenge to a DebateSend a Message 1/7/2014 3:16:45 AMPosted: 4 years agoAt 1/7/2014 3:14:38 AM, chui wrote:At 1/6/2014 6:08:30 PM, Ramshutu wrote:At 1/6/2014 6:28:31 AM, chui wrote:At 1/5/2014 5:18:45 PM, Ramshutu wrote:At 1/2/2014 6:41:48 PM, Installgentoo wrote:moving at 100m/s^2 why doesn't it move at 300,000m/s^2+100m/s^2?It does. Sort of.If we assume you are shining it out of the front of the train and you somehow measure it, ....This is an important point. How do we measure speed.The speed of light is pretty easy; you can look at discontinuities in orbits of Io, as Roemer did (and came bloody close), modern day you can measure round trip times with lasers and mirrors.....you will measure it as travelling at 300Mm/s, if you know you're travelling at 100m/s (224mph), that will work out as 300.001Mm/s.This is an inference that cannot be directly measured.Which is why I said sort of.However if you're travelling at this speed, time slows down very slightly (and distance gets a little shorter),...Only an external observer would see a change in time and distance. For you time and space do not change.Well, yes. This is really only a semantic error, though....so that while you measure it as 300.001Mm/s,You mean this is an inferred speed of light relative to objects moving relative to you. The direct measurement will be the speed of light.Yes. Hence the "sort of".someone else that is standing still compared to you will measure it as 300Mm/s.Relative to themselves.Well, yes. This is really only a semantic error, though.It's all down to relative speeds of observers. Remember the train isn't moving at 100m/s, it is moving 100m/s plus the contribution of the rotation of the earth, and the orbit of the earth around the sun, and the sun around the galactive centre, and the relative motion of the galaxy to other galaxies.But also in a very real sense the train is stationary.Well, yes. My main aim here was to try and boil down the complexity of the theory for the originating troll. I could have gone to the pure theoretical relativity (special or general), but I suspect the OP would have lost patience and started trying to pick fleas of me.A fair point. In that light I understand your initial post here.I don't blame you. My pedantometer would have been twitching at my post too :)