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# simple relativity question

Fri 22 Aug, 2008 02:15 pm
Using the standard Lorentz time-dilation formula, I calculated that one reference frame must be passing another reference frame at approximately .866 x c (the speed of light) in order for any observer in each of the two reference frames to think that the clocks in the other reference frame were running half as slow. Is this correct?
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Type: Question • Score: 8 • Views: 8,429 • Replies: 23
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cicerone imposter

1
Fri 22 Aug, 2008 05:15 pm
@ralphiep,
This q's way beyond my grade level.
0 Replies

1
Fri 22 Aug, 2008 05:22 pm
ralphiep wrote:
simple relativity question

0 Replies

2
Fri 22 Aug, 2008 05:34 pm
@ralphiep,
Wikipedia says you're right:

Code:```Speed Lorentz factor Reciprocal β = v / c γ 1 / γ 0.010 1.000 1.000 0.100 1.005 0.995 0.200 1.021 0.980 0.300 1.048 0.954 0.400 1.091 0.917 0.500 1.155 0.866 0.600 1.250 0.800 0.700 1.400 0.714 0.800 1.667 0.600 0.866 2.000 0.500 0.900 2.294 0.436 0.990 7.089 0.141 0.999 22.366 0.045 ```

http://en.wikipedia.org/wiki/Lorentz_factor
0 Replies

Thomas

2
Fri 22 Aug, 2008 07:31 pm
@ralphiep,
That's correct.
0 Replies

Seed

2
Sat 23 Aug, 2008 08:45 am
@ralphiep,
im still stuck on the word Using
0 Replies

Kevin Sorbello

1
Wed 22 Feb, 2017 09:34 am
@ralphiep,
Yes...and no. Your question does not specify the velocity of either observer, so in order for it to be true in all cases, it would have to be true for a situation where each observer was traveling at .433 x c...and that is not the case. Just as the mass of one observer does not increase simply because another is traveling past the observer at relativistic speeds, so too does the reduction in time passage not change due to relative motion. The clock of the traveler going .866 x c would appear slower to the observer "at rest", while the clock of the observer at rest would appear to be moving twice as fast to the observer traveling at .866 x c. The relativistic effect is not just an apparent change in time passage or length, it is an actual change in how time passes for the observer traveling at relativistic speeds.
maxdancona

2
Wed 22 Feb, 2017 09:44 am
@Kevin Sorbello,
1) This is an old question that has already been answered by Thomas (who actually understands Physics).

2) Kevin's post is nonsense.
layman

1
Wed 22 Feb, 2017 09:46 am
@Kevin Sorbello,
Kevin Sorbello wrote:

Yes...and no. Your question does not specify the velocity of either observer, so in order for it to be true in all cases, it would have to be true for a situation where each observer was traveling at .433 x c...and that is not the case.

If you're talking about special relativity, that theory REQUIRES that both travellers regard themselves as "at rest," whether they're actually moving or not. If ya don't do that, then it aint SR.

Also, nobody "sees" the other clock go slower. They deduce it from postulated assumptions, that's all.

If each observer actually "saw" the other clock running more slowly, then one of them would be hallucinating. So much for SR, eh?

Fact is, as the GPS and experiments like the Hafele-Keating one demonstrate, only one (not both) of two clocks actually runs slower than the other due to speed differential.

Even without empirical evidence of this fact, logic would preclude the conclusion that "each clock runs slower than the other."
maxdancona

1
Wed 22 Feb, 2017 09:50 am
@layman,
Not you Layman! I left the other thread when it was clear you weren't ever going to actually take the time to learn anything. Your understanding of relativity REQUIRES that everyon human being lives in Chicago.

Just because you don't understand it, doesn't mean it isn't correct. Are you going to spam up every Physics thread?
layman

1
Wed 22 Feb, 2017 09:54 am
@maxdancona,
Sorry to be blunt, Max, but you are an obtuse fool when it comes to this topic.
McGentrix

1
Wed 22 Feb, 2017 10:01 am
maxdancona

1
Wed 22 Feb, 2017 10:03 am
@layman,
For anyone who cares about my little spat with Layman....

Layman has admittted that he has never taken a college Physics course. He has read some stuff on the Internet that has given him the ability (so he thinks) to deny the standard Physics that is accepted by 99% of the scientific community. He has found a few fringe physicists that he claims supports his contrary ideas... and he takes quotes from some well-known Physicists out of context to support his view.

I have suggested on several occasions that Layman take a basic college course on Physics which would clear up several of his misconceptions. So far he has declined.
0 Replies

maxdancona

1
Wed 22 Feb, 2017 10:05 am
@McGentrix,
Why are you bothering to post at all McGentrix. You were part of the last spat... and you feel compelled to jump into this one to express your displeasure?

Oh the irony!
0 Replies

layman

1
Wed 22 Feb, 2017 10:05 am
@McGentrix,
Care to point out even ONE thing I said in that post, whether about theory, fact, or anything else, that you claim is wrong, Gent?

layman

1
Sun 26 Feb, 2017 05:54 pm
@layman,
No? That's what I thought.
layman

1
Sun 26 Feb, 2017 07:22 pm
@layman,
It takes some thinking to analyze the theoretical problems with SR.

A pre-condition of doing that is the willingness to think, which is conspicuously absent.

I haven't seen much of that from you guys (Max and Gent) with respect to this topic. All I hear is non-sequiturs, and all I see is the evasion of questions.
maxdancona

1
Sun 26 Feb, 2017 07:53 pm
@layman,
Get over yourself Layman. Real science is done by people who have taken the time to study the math and the physics. You don't do science by reading out of context quotes from the internet.

Disputing the work done by Einstein and Feynman and accepted by 99% of the scientific community is something that you should attempt after you have taken some time to study Physics. If you don't know calculus, then you are at a disadvantage.

I could point out the mistake you made in this thread, and I would if I thought it would do any good. Rather than looking at it mathematically, what you will do is go to google to find some site that supports your misconception (probably because you don't have the tools to understand it).

Education is an important thing... particularly when it comes to modern science.

layman

1
Sun 26 Feb, 2017 08:06 pm
@maxdancona,
Heh, Max, more bloviating with (completely uninformed) resort to fallacious ad populum, ad verecundiam, and ad hominem "arguments," eh? It's old, sorry.

1. For about the 1,000th time, math has absolutely NOTHING to do with the issues I raise.

2. I have never disputed Feynman. On the contrary I have cited his resolution of the "twin paradox" as saying the exact thing I (and millions of others) am saying.

3. You couldn't begin to "point out" my" mistakes," because you don't even know what the topic is. Furthermore, you have repeatedly demonstrated your lack of understanding of the theory of SR, as opposed to LR.

4. Yes, education is important. So why don't you educate yourself on a topic before pretending to have an answer, eh?
maxdancona

1
Sun 26 Feb, 2017 08:20 pm
@layman,
1. Of course it does. And the fact that you have said it 1,000 times doesn't change that fact.

2. Feynman believed in Relativity. He taught relativity. When you claim that you have non-mathematical knowledge that overturns relativity, you are disputing Feynman.

3. You are right. I have never been able to point out your mistakes to you. But that says more about you than it does about me.

4. I have a Physics degree (as did Einstein and Feynman). I have actually taken courses in Relativity. In other words, I have educated myself. And, I have suggested many time that you would do well to pick up a Physics 101 text book before you try to disprove a core idea of modern science

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