Verifying Equations 9.45 & 9.46 in Schutz, pg. 224

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In summary, the discussion is about equations from Schutz, A First Course in GR and the attempt to verify equations 9.45 and 9.46 using equations 9.43 and 9.44. After unsuccessful attempts, it is concluded that equation 9.45 is likely incorrect and the correct version should be R = \frac{1}{2}l_{0}\Omega^{2}A/[(\omega_{0}{}^{2} - \Omega^{2})^2 + 4\Omega^{2}\gamma^{2}]^{1/2}. The justification for this is found by looking at equation 9.46 and correcting it to tan \phi = -2\gamma \Omega /
  • #1
Jimmy Snyder
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This question is just for those who have a copy of Schutz, A First Course in GR. I have tried to plug equations 9.43 and 9.44 into equation 9.42 in order to verify equations 9.45 and 9.46. So far, I have not been successful. However, I have come to the conclusion that probably 9.45 is incorrect. The book has:
[tex]
R = \frac{1}{2}l_{0}\Omega^{2}A/[(\omega_{0} - \Omega)^2 + 4\Omega^{2}\gamma^{2}]^{1/2}
[/tex]
But I believe it should be the following:
[tex]
R = \frac{1}{2}l_{0}\Omega^{2}A/[(\omega_{0}{}^{2} - \Omega^{2})^2 + 4\Omega^{2}\gamma^{2}]^{1/2}
[/tex]
Unfortunately, I haven't been able to successfully justify either equation. The reason I think that my version may be the correct one is by looking at equation 9.46
[tex]
tan \phi = 2\gamma \Omega / (\omega_{0}{}^{2} - \Omega^{2})
[/tex]
which implies:
[tex]
cos \phi = (\omega_{0}{}^{2} - \Omega^{2}) / [(\omega_{0}{}^{2} - \Omega^{2})^2 + 4\Omega^{2}\gamma^{2}]^{1/2}
[/tex]
 
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  • #2
jimmysnyder said:
This question is just for those who have a copy of Schutz, A First Course in GR. I have tried to plug equations 9.43 and 9.44 into equation 9.42 in order to verify equations 9.45 and 9.46. So far, I have not been successful. However, I have come to the conclusion that probably 9.45 is incorrect. The book has:
[tex]
R = \frac{1}{2}l_{0}\Omega^{2}A/[(\omega_{0} - \Omega)^2 + 4\Omega^{2}\gamma^{2}]^{1/2}
[/tex]
But I believe it should be the following:
[tex]
R = \frac{1}{2}l_{0}\Omega^{2}A/[(\omega_{0}{}^{2} - \Omega^{2})^2 + 4\Omega^{2}\gamma^{2}]^{1/2}
[/tex]
Unfortunately, I haven't been able to successfully justify either equation. The reason I think that my version may be the correct one is by looking at equation 9.46
[tex]
tan \phi = 2\gamma \Omega / (\omega_{0}{}^{2} - \Omega^{2})
[/tex]
which implies:
[tex]
cos \phi = (\omega_{0}{}^{2} - \Omega^{2}) / [(\omega_{0}{}^{2} - \Omega^{2})^2 + 4\Omega^{2}\gamma^{2}]^{1/2}
[/tex]
Yes I get it to work out with your correction
[tex]
R = \frac{1}{2}l_{0}\Omega^{2}A/[(\omega_{0}{}^{2} - \Omega^{2})^2 + 4\Omega^{2}\gamma^{2}]^{1/2}
[/tex]
and the additional correction that
[tex]
tan \phi = -2\gamma \Omega / (\omega_{0}{}^{2} - \Omega^{2})
[/tex]
 
  • #3
mitchellmckain said:
and the additional correction that
[tex]
tan \phi = -2\gamma \Omega / (\omega_{0}{}^{2} - \Omega^{2})
[/tex]
Thank you, thank you, thank you, thank you. I have spent hours on this one equation trying many different tricks, but somehow this one escaped me.
 

1. How do you verify equations 9.45 and 9.46 in Schutz, pg. 224?

To verify these equations, you can start by checking the definitions and assumptions used in the equations. Then, substitute the given values into the equations and solve for the variables. Finally, compare the results to the original equations to ensure they are equal.

2. Can equations 9.45 and 9.46 be verified experimentally?

Yes, these equations can be verified experimentally by conducting experiments that involve the variables in the equations and comparing the results to the predicted values using the equations. This can help validate the accuracy and applicability of the equations.

3. Are there any limitations to these equations?

Like any scientific equation, equations 9.45 and 9.46 may have limitations depending on the specific scenario or conditions they are applied to. It is important to understand the assumptions and conditions under which these equations were derived to ensure their accuracy and applicability.

4. What is the significance of equations 9.45 and 9.46 in Schutz, pg. 224?

Equations 9.45 and 9.46 are used to describe the behavior of certain physical phenomena, specifically the behavior of a body in a gravitational field. They are significant because they help us understand and predict the motion of objects in a gravitational field and have been verified through experiments and observations.

5. Are there any alternative equations that can be used instead of 9.45 and 9.46?

There may be alternative equations that can describe the same physical phenomenon, but equations 9.45 and 9.46 are widely accepted and used in the scientific community. It is important to understand the context and assumptions behind any alternative equations before using them in place of these equations.

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