How does the Earth's rotation affect time and weight at different latitudes?

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Discussion Overview

The discussion revolves around the effects of Earth's rotation on time and weight at different latitudes, specifically comparing conditions at the North Pole and the Equator. It includes considerations of centripetal acceleration, gravitational forces, and the implications of special and general relativity on time measurement.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant notes the speed of the Earth's surface at the Equator is about 460 m/s and questions the centripetal acceleration experienced by an atomic clock moved from the North Pole to Ecuador.
  • Another participant corrects the speed to approximately 465 m/s and discusses the implications of using different units of measurement, expressing a preference for the SI unit system.
  • Concerns are raised about the altitude differences between the two locations, with one participant questioning the validity of comparing clocks at the same altitude when the altitude in Ecuador varies significantly.
  • Participants discuss the formula for centripetal acceleration and the gravitational force acting on the clocks, suggesting calculations for the weight of the clock in Ecuador.
  • There is mention of time dilation effects at different latitudes according to both special relativity (SR) and general relativity (GR), with one participant expressing reluctance to perform the calculations themselves.
  • One participant challenges another on the clarity of their arguments and the assumptions made regarding the altitude comparison.
  • Humor and sarcasm are used throughout the discussion, particularly regarding the use of units and the nature of the problem posed.

Areas of Agreement / Disagreement

Participants exhibit disagreement on several points, including the correct speed of the Earth's rotation, the relevance of altitude comparisons, and the interpretation of gravitational effects. The discussion remains unresolved with multiple competing views presented.

Contextual Notes

Participants express uncertainty about the assumptions made regarding altitude and the effects of relativistic physics on time measurement. There are also unresolved mathematical steps related to the calculations of centripetal acceleration and gravitational force.

Who May Find This Useful

This discussion may be of interest to those exploring the implications of Earth's rotation on physical measurements, as well as individuals interested in the interplay between relativity and practical applications in physics.

RandallB
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With a speed of about 460m/s for the Earth's surface at the Equator as it spins around its axis.

Using 2 Atomic Clocks tested to be accurate and match each other and both weighing exactly 100 lbs at an arctic lab site pretty much at the north pole.
Moving one clock to Ecuador pretty much on the Equator and the same altitude (as measured from the center of the earth) for one year.

How much “centripetal acceleration” would it feel from the Earth's rotation?

How much will the clock weigh in Ecuador?

After bringing the two clocks back together how will the time on the Ecuador clock compare to the Polar Clock? How much and why for any difference.
 
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RandallB said:
With a speed of about 460m/s for the Earth's surface at the Equator as it spins around its axis.

That's about 465m/s.

RandallB said:
Using 2 Atomic Clocks tested to be accurate and match each other and both weighing exactly 100 lbs at an arctic lab site pretty much at the north pole.

You know there are much more people on this planet using the SI-MKgs unit sytem.Or do you really hate the French that much as not to use their units...?? :-pThat's round 45.3Kg.And for the length,the unit,one inch,coming from the little finger of one of the hands of king Henry the VIII-th...God,that's sick! What if king Henry had lost his hands in a battle?They woulkd have changed the unit? :smile: :-p

RandallB said:
Moving one clock to Ecuador pretty much on the Equator and the same altitude (as measured from the center of the earth) for one year.

The altitude in Ecuador varies in the range 0->6310 (the frozen peak of Chimborazo volcano).So taking the Arctic lab at see level,the difference in heights between the labs would vary in the domain (21-27) Km.So the part with the same altitude measured from the center of the Earth makes no sense to me.Perhaps u'd like to explain...

RandallB said:
How much “centripetal acceleration” would it feel from the Earth's rotation?

Why ask us??Don't u know to compute a_{cp}=\omega^{2}R_{eq} ?

RandallB said:
How much will the clock weigh in Ecuador?

Gravity force:F=G\frac{M_{clock}M_{Earth}}{(R_{eq}+h)^{2}}Compute.Earth's mass round 6\cdot 10^{24}Kg.Cavendish constant can be taken from a table of fundamental constants.The Earth's radius at equator is approximately 6378000m,"h" goes from 0->6310 m (see above for explanation).I assumed no relativistic effects on the mass.No effects from SR or GR.

RandallB said:
After bringing the two clocks back together how will the time on the Ecuador clock compare to the Polar Clock? How much and why for any difference.

Times goes differently at Equator than it goes at the Pole according to both SR and GR.i don't feel like making this sorts of calcultions.Do them yourself... :-p

Daniel.

PS.Where do you bring the 2 clocks back together,at what speed (or even acceleration) do you bring them?
 
Last edited:
dextercioby said:
That's about 465m/s.
Got to give you that one Danny - 465 is about 460 only 'about' 1% diff
OR maybe you'd prefer the aprox. speed and % to two decimals. With m being so long and inexact would you prefer a unit a little shorter like foot or inch?
dextercioby said:
You know there are much more people on this planet using the SI-MKgs unit sytem.Or do you really hate the French that much as not to use their units...?? That's round 45.3Kg.And for the length,the unit,one inch,coming from the little ...
Oops – guess inch is out eh.
How can anyone so anal get the Units for Force and weight wrong?
( Or do you think you can answer the question “In grams, how much does a 100 gram weight weigh on the moon – ‘about’)
And since you were first to bring up inch – WHY? Did you think this was a history thread. And what’s up with ‘French’ – you have some kind of England France conflict going on in your head?
dextercioby said:
The altitude in Ecuador varies in the range 0->6310 (the frozen peak of Chimborazo volcano).So taking the Arctic lab at see level,the difference in heights between the labs would vary in the domain (21-27) Km.So the part with the same altitude measured from the center of the Earth makes no sense to me.Perhaps u'd like to explain...
Let see maybe to keep the same altitude! You may construct a tower at the pole – I’d suggest using your imagination.
dextercioby said:
Why ask us??Don't u know to compute a_{cp}=\omega^{2}R_{eq} ?
Not so much for you but for those that might want enjoy working on a problem.If I really had clocks and dog sled ready to go, I’d have posted in another area.
But I do approve of shareing Formulas with everyone - that's nice of you.
dextercioby said:
Gravity force:F=G\frac{M_{clock}M_{Earth}}{(R_{eq}+h)^{2}}Compute.Earth's mass round 6\cdot 10^{24}Kg.Cavendish constant can be taken from a table of fundamental constants.The Earth's radius at equator is approximately 6378000m,"h" goes from 0->6310 m (see above for explanation).I assumed no relativistic effects on the mass.No effects from SR or GR.
Gee Danny I think I got to mark you down a point on that one. You missed a conversion or translation – try looking up “the same altitude”.
dextercioby said:
Times goes differently at Equator than it goes at the Pole according to both SR and GR.i don't feel like making this sorts of calcultions.Do them yourself...
Gosh Danny based on the problem as defined this is the only fun part to work on - come back when your more in the mood.QUOTE=dextercioby]
PS.Where do you bring the 2 clocks back together,at what speed (or even acceleration) do you bring them? [/QUOTE]Well just for you I'll give some grownup bonus points if you can show how anywhere on Earth at any speed could affect the clocks to make any significant differance.
 
RandallB said:
Got to give you that one Danny - 465 is about 460 only 'about' 1% diff.

I see u haven't looked in an atlas for years...If u had,u didn't do it with the glasses on.That's how 460 got on the retina instead of 465. :-p

RandallB said:
OR maybe you'd prefer the aprox. speed and % to two decimals.

I guess u missed the point.My figure didn't include decimals.I wouldn't have expected u put the decimals.But at least the (VERY) significant digits... :wink:


RandallB said:
With 'm' being so long and inexact would you prefer a unit a little shorter like foot or inch? Oops – guess inch is out eh.

Since it relies on the decimal basis and the decimal system,i guess the meter is irreplaceble.

RandallB said:
How can anyone so anal get the Units for Force and weight wrong?

To make a bad joke,the word 'anal' has other meanings as well... :wink:
Who got the units for Force and Weight wrong??
RandallB said:
( Or do you think you can answer the question “In grams, how much does a 100 gram weight weigh on the moon – ‘about’)

I assume this is a joke...A lousy oe,that is... :-p

RandallB said:
And since you were first to bring up inch – WHY? Did you think this was a history thread. And what’s up with ‘French’ – you have some kind of England France conflict going on in your head?

:smile: Apparently u have...Who brought it up?? :wink:
RandallB said:
Let see maybe to keep the same altitude! You may construct a tower at the pole – I’d suggest using your imagination.

Bad suggestion!Since entering Phyics Department at my hometime university,my imagination tends to take into account science.It therefore cannot conceive building a 21->27Km tower at the pole.Or you thought of this as a 'Gedankenexperiment'??You know,Einstein's imagination used to rely to science too... :wink:


RandallB said:
Gee Danny I think I got to mark you down a point on that one. You missed a conversion or translation – try looking up “the same altitude”.

Have been reading my post without glasses??I guess it seemed like an atlas and u decided it's better if u took out your glasses... :wink:

RandallB said:
Gosh Danny based on the problem as defined this is the only fun part to work on - come back when your more in the mood

Now that's something really funnny... :smile: :smile: Finally u made a good joke... :-p

RandallB said:
Well just for you I'll give some grownup bonus points if you can show how anywhere on Earth at any speed could affect the clocks to make any significant differance.

That should have probably offended me,but I'm "different".'Gosh',if it didn't make any 'significant differance',then how come 'this is the only fun part to work on'?

Daniel.For you,and only for you:'Danny'. :-p
 
Did you look up "About" -- fine use Decameter 46 save it you want 47 I know.

You were first to use anything but metric for Length – need your glasses to read the posts?

You were first to use Grams for Weight – noticed you didn’t try to answer – maybe because using your units for weight it cannot be done.

If you cannot answer any of them – just leave to someone else.
Or did you need a separate Thread area for cracking Wise.

But if you do find the time how about using the Decimal version of time the French tried to make metric.
 
RandallB said:
Did you look up "About" -- fine use Decameter 46 save it you want 47 I know.

Wow,u keep trying to make jokes... :-p

RandallB said:
You were first to use anything but metric for Length – need your glasses to read the posts?

I don't know if you need my glasses.I have mixed astigmatism at both eyes...I gave "inch" as an example of how ridiculous does your unit system look to me.And i gave my reasoning a historical grounding.Besides,u started with "lbs.". :wink:

RandallB said:
You were first to use Grams for Weight – noticed you didn’t try to answer – maybe because using your units for weight it cannot be done.

Show me that post and i'll delete it by eating it... :-p What cannot be done using my units (i hope you mean:Kilogram and meter) ?

RandallB said:
But if you do find the time how about using the Decimal version of time the French tried to make metric.

Good joke,but that missing comma makes it imperfect... :wink:

Daniel.
 
well, off course, the clock in ecuador, will weigh more due to centripetal acceleration, but i am not in a mood to calculate all that.

but as far as the time difference is concerned, i think that the concept of time dilation is applied only in case the velocity is of the order of 'c' which is not the case here, hence SR cannot be applied here, neither can GR be applied as both the places have no relative acceleration.
 
vikasj007 said:
well, off course, the clock in ecuador, will weigh more due to centripetal acceleration, but i am not in a mood to calculate all that.

I'm afraid it's the other way around.It will weigh less,due to the centrifugal effect created by the Eatrth's rotation.It'a acceleration due to Earth's rotation is a_{cfi}=\omega^{2} R_{equator},sot that the weight force will be
\vec{G}=m(g_{equator}-\omega^{2} R_{equator})\vec{j}

vikasj007 said:
but as far as the time difference is concerned, i think that the concept of time dilation is applied only in case the velocity is of the order of 'c' which is not the case here, hence SR cannot be applied here, neither can GR be applied as both the places have no relative acceleration.

Both theories can be applied.GR can be applied due to the fact that Earth creates different gravitational fields at the poles and at the equator.

Daniel.
 

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