# Recent content by belliott4488

1. ### Appropriate distribution for minimum distance

Ah, okay - that makes sense. I was kind of hoping someone might say, "Oh, this is what so-and-so developed the so-and-so distribution to describe." There are so many distribution functions out there, and I know very little about most of them. I wish I could post some data or plots or...
2. ### Appropriate distribution for minimum distance

I apologize again for over-simplifying the problem. These trajectories are actually the output of fairly complex 6-degree-of-freedom simulations, so I can't really even attempt to give the all the details. (Truthfully, I don't know all of them - there are all kinds of mechanical systems, the...
3. ### Appropriate distribution for minimum distance

Sorry - didn't mean to imply that they're 2-D. In fact, they're 3-D trajectories, and they're not truly ballistic (there's powered flight involved). For the sake of this question, I think we can make the approximation that they are projectiles that originate from a fixed point in space, and the...
4. ### Appropriate distribution for minimum distance

I have what I think is probably a basic question from probability and statistics (about which I'm pretty ignorant). If I have a set of projectile trajectories that were generated by a Monte Carlo process, and I'd like to know the probability the projectile will come within distance d of some...
5. ### How does GR describe acceleration from non-gravitational forces?

Yes - I was speaking sloppily again. What I really meant was that rocket guy is not near a gravitating body, so his spacetime is flat (that's all I meant by "local"), and mine is very much near a massive body, so mine is curved. Thanks again.
6. ### How does GR describe acceleration from non-gravitational forces?

I think I would have said that even before today, although I suspect I wouldn't have understood what I was saying - or slightly less than I do now, anyway. So, let's see - when I stand on the surface of the Earth, I am prevented from following a geodesic on my locally curved bit of spacetime...
7. ### How does GR describe acceleration from non-gravitational forces?

Thanks to all - I knew I had a pretty fundamental misunderstanding, and these responses have all helped a lot. I think I was suffering from the cartoon understanding of the observer in a uniformly accelerating elevator who cannot distinguish between that and a stationary elevator in a uniform...
8. ### How does GR describe acceleration from non-gravitational forces?

I have a pretty basic question - one that should have occurred to me long ago, but I never really thought about before. We all know how the effects of gravity are described by the curvature of spacetime - rubber sheets and all that - as well as the equivalence of inertial and gravitational...
9. ### Who first assigned negative to electrons and positive to protons?

I find this to be an odd discussion. The assignment of a sign to the current was made long before there were any direct observations of the actual charge carriers (as was noted in an earlier post). As far as the scientists at the time were concerned, electricity was the flow of some kind of...
10. ### Fortran How to move on from Compaq Visual Fortran

Thanks, all. I chose Simply Fortran because it is based on the GNU compiler but also provides a nice IDE. It's inexpensive - compared to Intel Fortran, at least - so I'm trying to see if I can get everything working with it before I bite the bullet (or have my employer do it) to get Intel...
11. ### Fortran How to move on from Compaq Visual Fortran

My group at work uses several pieces of legacy Fortran code which we've always compiled using Compaq Visual Fortran. Since CVF has not been supported for while now and is not (easily) compatible with Windows 7, I'd like to move to a more up-to-date compiler and IDE. I'm trying Simply Fortran...
12. ### Web link for crackpot test?

Update: After announcing the he has been told "never to try to do physics again", he has now compared himself to Gallileo and Copernicus. 40 more points!! :biggrin:
13. ### Pair-production - how come it's always e+e-, never muons or tauons?

When I was in grad school there was an older professor who consistently called it a "tauon". He also consistently referred to the muon as the "mu meson" - as it had originally been called, due to the similarity in pi and mu masses - although by then that was considered to be flat-out wrong...
14. ### Web link for crackpot test?

Actually, he didn't score too badly. He's not as far over the top as others I've seen, but he does suffer from the syndrome of saying things along the lines of, "I have a novel approach to the fundamental underpinnings of all of Physics, which explains a host of things the 'Standard Model' [his...
15. ### Web link for crackpot test?

No - the Baez one was it - but this one is more serious and has some value for that reason. Thanks.