Talk:Circular orbit

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WTF[edit]

I don't know if I'm just retarded and I'm missing something complete obvious, but it seems to me that the speed is given by v=\sqrt{2\mu\over{r}} and not v=\sqrt{\mu\over{r}}. I mean, the kinetic energy is mv^2\over{2} and the potential energy is :-GMm\over{r}. On the orbit, total energy is minimized (E=0).

Therefore :v=\sqrt{2\mu\over{r}} .

This error carries on to the period. T=\pi\sqrt{2r^3\over{\mu}} not T=2\pi\sqrt{r^3\over{\mu}}

And also, if we're talking about circular orbits, might as well give the real orbital energy conservation equation {v^2\over{2}}-{\mu\over{r}}=0 . I have no clue why it was equal to something other than 0 before.

It's as if someone went through this and purposely screwed things up. Anyway I cleaned things up.

Headbomb 03:22, 17 May 2007 (UTC)

The energy is not zero. The formulas were correct.--Patrick 12:53, 22 June 2007 (UTC)

Equation of Motion, delta V and Virial theorem[edit]

The equation of motion became redundant, and I really don't see what mentionning the Virial theorem or the delta V brought to the topic. Headbomb 03:33, 17 May 2007 (UTC)

I restored it.--Patrick 12:58, 22 June 2007 (UTC)

Orbital velocity in general relativity[edit]

Is the orbital velocity of circular orbits in general relativity exactly the same as in the Newtonian case or are there any subtle differences? Agge1000 12:57, 11 November 2007 (UTC)

I'm aware this is an old question, but it looks bad unanswered. Yes, there are differences and I attempted to describe how to calculate the speed in GR. Xavath (talk) 23:34, 21 February 2012 (UTC)

More details please[edit]

This is the first time I'm looking at these equations, can someone clarify what the two different R's are in the equation: \mathbf{a} = - \frac{v^2}{r} \frac{\mathbf{r}}{r} = - \omega^2 \mathbf{r} — Preceding unsigned comment added by Nhilton (talkcontribs) 20:07, 27 September 2012 (UTC)

As far as I can tell, \mathbf{r} in all cases is radius. I do not understand why it is presented as it is, and further, the article Circular_motion#Uniform_circular_motion presents the formula as  a\, = \frac {v^2} {r} \, = {\omega^2} {r}  , and for the sake of clarity, I am going to replace the former with the later. T.Randall.Scales (talk) 19:43, 2 January 2015 (UTC)

standard gravitational parameter does not agree with link.[edit]

The definition of the standard gravitational parameter from here:

http://en.wikipedia.org/wiki/Standard_gravitational_parameter   

does not agree with the text from here:

http://en.wikipedia.org/wiki/Circular_orbit#Velocity  — Preceding unsigned comment added by 98.125.78.211 (talk) 09:05, 19 February 2015 (UTC)