I with an exercise about Energy and Schwarzschild Black Holes

In summary: Thanks for understanding! Actually it's I who need to apologize. I have checked the homework help guidelines and they do allow the person asking the question to post a solution if they find one:So it's OK for you to post your solution. Thanks for understanding!
  • #1
JTorn
6
0
Homework Statement
Deadline : 18 of November
Relevant Equations
SW orbital equations adn Newtonian mechanical Energy
The thing is that this is an exercise that I have to show my teacher but I don´t know how to get the answer.The exercise says:

"A body of mass m moving in the Keplerian field V = −M/r (in G = 1 units) has a total conserved energy, Etot = 1 /2( m r˙^2 + r ^2ϕ˙ ^2 )− mM/r.

Show that the Newtonian limit of the Schwarzschild orbital equations leads to this same expression; use this calculation to obtain Etot. "

I tried starting from r·^2 = E - ( 1 - 2M/r)(1-L^2/(m^2)) using L = r^2 ϕ· but I cannot get rid of some squares.

Any help?
 
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  • #2
JTorn said:
I tried starting from r·^2 = E - ( 1 - 2M/r)(1-L^2/(m^2))

You might want to check this equation; it's a good one to start from but I think you have some factors wrong.
 
  • #3
PeterDonis said:
You might want to check this equation; it's a good one to start from but I think you have some factors wrong.

Sorry, I'm new here and i don't know how to write equations properly, the equation is fine, it's just that I am using G=c=1 units.

I have completed the exercise and I will upload the answer as soon as possible but now I'm quite busy trying to complete other exercises.

Thanks you.
 
  • #4
JTorn said:
the equation is fine

I'm not sure it is, as you wrote it.

JTorn said:
it's just that I am using G=c=1 units.

I know that. That's not the issue I was talking about.
 
  • #5
JTorn said:
I will upload the answer

You shouldn't post the answer here explicitly since this is a homework forum.
 
  • #7
[QUOTE = "PeterDonis, publicación: 6260852, miembro: 197831"]
No debe publicar la respuesta aquí explícitamente you que este es un foro de tareas.
[/ CITAR]

I'm really really sorry. I did not read the rules. Now I know them.
 
  • #8
Oh, I didn't know I could use Látex code here. Sorry for my ignorance and Thank you very much.
 
  • #9
PeterDonis said:
You shouldn't post the answer here explicitly since this is a homework forum.

JTorn said:
I'm really really sorry. I did not read the rules. Now I know them.

Actually it's I who need to apologize. I have checked the homework help guidelines and they do allow the person asking the question to post a solution if they find one:

micromass said:
Complete solutions can be provided to a questioner after the questioner has arrived at a correct solution. If the questioner has not produced a correct solution, complete solutions are not permitted, whether or not an attempt has been made.

So it's OK for you to post your solution.
 
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FAQ: I with an exercise about Energy and Schwarzschild Black Holes

1. What is energy?

Energy is a physical quantity that describes the ability of an object or system to do work. It can exist in many forms, including kinetic, potential, thermal, and electromagnetic.

2. What is a Schwarzschild Black Hole?

A Schwarzschild Black Hole is a theoretical object in space that is formed when a massive star dies and its core collapses under its own gravity. It is characterized by a singularity at its center and an event horizon, beyond which nothing, including light, can escape.

3. How does an exercise about Energy and Schwarzschild Black Holes relate to each other?

This exercise combines two important concepts in physics – energy and black holes. It allows us to explore the relationship between energy and gravity, and understand how black holes affect the surrounding space and objects.

4. What can we learn from studying Energy and Schwarzschild Black Holes?

Studying energy and black holes can help us understand the fundamental laws of physics and the behavior of matter and energy in extreme conditions. It also has practical applications in fields such as astrophysics, cosmology, and space travel.

5. Are Schwarzschild Black Holes real?

While we have not directly observed a Schwarzschild Black Hole, their existence is supported by mathematical equations and observations of the effects of their gravity on surrounding objects. However, further research and observational evidence are needed to fully understand these mysterious objects.

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