Exercise 2.5 in Misner, Thorne and Wheeler

In summary, the conversation discusses the issue of having a component v0=0 when the squared length of a 4-velocity is -1. The speaker mentions playing with equation (2.35) and producing a result of v=γ(-u2,-u1,-u2,-u3), which does not have a squared length of -1. Another person, TerryW, asks for clarification and Bill_K responds by explaining that in Exercise 2.5, u is the particle's 4-velocity with a squared length of -1, while v is a newly defined spacelike vector. Bill_K also suggests that some additional explanation in the text could have helped clarify this concept. The conversation ends with TerryW
  • #1
TerryW
Gold Member
191
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If the squared length of a 4-velocity is -1, how can you have a component v0 =0?

I've played with equation (2.35) and produced a result of v = γ(-u2, -u1, -u2, -u3), which doesn't have a squared length of -1.

Can anyone help out?



TerryW
 
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  • #2
In Exercise 2.5, u is the particle's 4-velocity with squared length -1, whereas v is a newly defined spacelike vector, apparently the projection of u onto the observer's space section.
 
  • #3
Thanks

Hi Bill_K,


So my result is probably OK. A few words along those lines in the text hinting at the special nature of v might have helped, it does come out of left field a bit.

Thanks for your prompt reply. You obviously don't subscribe to the view I saw in one post that if you are working through MTW, you should need any help!


Regards

TerryW
 

1. What is Exercise 2.5 in Misner, Thorne and Wheeler?

Exercise 2.5 in Misner, Thorne and Wheeler is a problem set found in their book "Gravitation", which is considered a standard textbook in the field of general relativity. It is a collection of exercises designed to help students understand and apply the concepts and equations related to gravitational physics.

2. Is Exercise 2.5 in Misner, Thorne and Wheeler difficult?

The difficulty of Exercise 2.5 in Misner, Thorne and Wheeler can vary depending on the individual's understanding and familiarity with the subject matter. However, as it is a standard textbook in the field, it is generally considered to have a moderate level of difficulty.

3. What topics does Exercise 2.5 cover?

Exercise 2.5 in Misner, Thorne and Wheeler covers a variety of topics related to gravitational physics, including the principles of general relativity, geodesic equations, and the Einstein field equations. It also includes exercises on gravitational waves, black holes, and cosmology.

4. How can I use Exercise 2.5 to improve my understanding of general relativity?

Exercise 2.5 is designed to help students apply the concepts and equations of general relativity to real-world problems. By completing the exercises and practicing the equations, you can improve your understanding of the subject and develop your problem-solving skills in the field of gravitational physics.

5. Are there any resources available to help with Exercise 2.5 in Misner, Thorne and Wheeler?

Yes, there are various resources available to assist with Exercise 2.5 in Misner, Thorne and Wheeler. These include online forums and study groups, as well as study guides and solutions manuals. Additionally, consulting with a professor or tutor in the field may also be helpful in gaining a better understanding of the exercises.

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