User talk:Wolfkeeper

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Orbit Unclarity

I read the article, Orbit, and I don't understand the cannonball scenario. Don't projectiles, such as the cannonball, follow parabolic paths? I suppose the eccentricity is an absolute value thing in this case where the orbit goes from parabolic to elliptical to circular to elliptical, then parabolic, again, and finally to hyperbolic. According to geometry, the eccentricity cannot be negative. I know that the shape of the orbit depends on the energy, i.e. the velocity. I suppose it's a matter of speed. For circular, neglecting air resistance, v=Failed to parse (syntax error): {\displaystyle (GM/r)^½} Kissnmakeup (talk) 18:57, 25 July 2008 (UTC)

Cannonballs are never parabolic, although the difference from parabolic flight (ignoring air drag) is extremely small in most everday circumstances. They're always elliptical, basically because the Earth surface is not flat. If the Earth was flat, then they would be parabolic.- (User) WolfKeeper (Talk) 19:11, 25 July 2008 (UTC)

(Actually, if you're being really pinickity, they're not elliptical either, they would only be elliptical if the Earth was perfectly spherically symmetric, but let's not go there.)- (User) WolfKeeper (Talk) 19:11, 25 July 2008 (UTC)

FWIW eccentricity is not primarily a matter of speed, although it is involved, for any given speed it's a matter of the direction at a point on the orbit.- (User) WolfKeeper (Talk) 19:11, 25 July 2008 (UTC)

More orbits

Thank you.

I'm studying for the GRE Physics test, and I have a question about a problem on an old practice test. Would you want to give it a whirl?

The problem is this (Test 9677 problem#66):

When it is about the same distance from the Sun as is Jupiter, a spacecraft on a mission to the outer planets has a speed that is 1.5 times the speed of Jupiter in its orbit. Which of the following describes the orbit of the spacecraft about the Sun? A) Spiral, B) Circle, C) Ellipse, D) Parabola, E) Hyperbola.

ETS says (E) Hyperbola. I say bull. According to Mechanics by Keith Symon, the shape of the orbital depends on the total energy, not just the kinetic energy. The mass of Jupiter is about 1.8 x 10^27 kg, while the Mars Global is about 1030 kg. This is a massive difference in potential energy. Does it not matter in light of the mass of the Sun which is 1048 Jupiters? I would think that it would matter. I mean, multiply it out. GMm/r Kissnmakeup (talk) 20:55, 25 July 2008 (UTC)

Because you told me it's homework, I'll give you just one hint: it's the specific total energy (total energy per kg) that matters, not the total energy.- (User) WolfKeeper (Talk) 21:09, 25 July 2008 (UTC)

It's not homework. This is a practice test from 1996, with published answers. I just don't agree with the answer that ETS published for it. But, I really appreciate your response. Thanks. Kissnmakeup (talk) 22:14, 25 July 2008 (UTC)

Really, it's a specific energy/escape velocity question, right? The mass of the body itself cancels out in the equations. (Actually the deep knowledge is that it's to do with Galileo all things fall the same under gravity.) The escape velocity at Jupiter's orbit is 18.5 km/s, and the orbital velocity is 13.07 km/s. Since 1.5*13.07 > 18.5 then it's a hyperbola.- (User) WolfKeeper (Talk) 22:32, 25 July 2008 (UTC)

Duh.

Thanks. Was it Galieo or Newton? Regardless, I was not happy with that classical mechanics book when I took the class, and I'm even less happy with it now. I'm getting a different one, and maybe even an astrodynamics text. All this orbit stuff is making my head spin.Kissnmakeup (talk) 00:57, 26 July 2008 (UTC)

Galileo. You probably heard the (probably apocryphal) story about cannonballs and the tower of piza etc. etc.- (User) WolfKeeper (Talk) 01:06, 26 July 2008 (UTC)

Edits to Magnetic levitation

I just noticed a massive deletion of content from that article. I'm assuming, based on your edit history, that it wasn't intentional on your part, but I wanted to let you know I reverted it. --GoodDamon 23:15, 1 August 2008 (UTC)

Access to the server messed up, and a combination of misfeatures messed up the text.- (User) WolfKeeper (Talk) 23:38, 1 August 2008 (UTC)

InternetHero

Enough is enough[1] - We've tried; we're failing. I'm going to put together an RFC for InternetHero, in the hope that others can help him change his behaviour to become a more a more effective editor, and more productive member of this community. Assuming you feel the statement and summary of the evidence that I put together are accurate, would you agree to endorse the request? (Note: I'm crossposting this to DigitalC) -- Mark Chovain 01:18, 7 August 2008 (UTC)

I'm pretty sure that would be OK.- (User) WolfKeeper (Talk) 02:14, 7 August 2008 (UTC)

Good luck, I've been nothing but compromising in this situation. I am simply trying to work some angles to include Alhazan (Al-Haytham) to the article, whether it be for the lead section of the history section. If there were something wrong with what I am doing (simply trying to contribute), then the admins would hav banned me already or given me a warning. They have been in the discussion before and have done no such thing beside the 3RR thing. I suggest a truce. InternetHero (talk) 01:33, 9 August 2008 (UTC)

Penis Size Graphs - Source(s)

Hello there! I was just curious as to where you got your penis size information data from that you used to create the graphs with. I know it was Ansell Research that carried out the information for Lifestyles Condoms. I know the average figures from that research are easy enough to come across but the other measurements to create graphs? I'd much appreciate any light you can shed on this matter. --Assisting Wiki (talk) 08:06, 8 August 2008 (UTC)

Opinion for telescope

Hey, thanks for your opinion on that article. I know we've had our problems, but its nice to see that you don't let the content suffer for it. InternetHero (talk) 01:34, 9 August 2008 (UTC)