# Search results for query: *

1. ### What is the coalescence factor?

I probably did something wrong when i tried to find the dimensions and yes i think you are right that c = 1 is implied. I got the equation from an old article called "Deuteron and triton production with high energy sulphur and lead beams". It's from 2001, so you might not be able to find it on...
2. ### What is the coalescence factor?

Of course, i didn't even consider that. Okay, so i guess the coalescence factor has dimensions of: \frac{ev^{2}s}{m} I'm still not sure exactly sure about what the coalescence factor is though.
3. ### What is the coalescence factor?

I am reading an article on experimental nuclear physics. The article is about deuteron and triton production in Pb + Pb collisions. In the article they mention the coalescence factor which is given by: B_{A}=A\frac{2s_{A}+1}{2^{A}}R^{N}_{np}\left(\frac{h^{3}}{m_{p}\gamma V}\right)^{A-1}...
4. ### What does A * Gev/c mean?

I think you're right. But i think the SPS was upgraded from 400 Gev to 450 Gev when it was to be used as a pre-accelerator for the LHC. The experiment from my article was done way back in 2000, when the SPS was probably still operating at 400 Gev.
5. ### What does A * Gev/c mean?

Ah, well that certainly explains it. Beautiful how the max energy of the sps works out to be exactly the energy mentioned in the article. Thank you for your help Bill!
6. ### What does A * Gev/c mean?

Okay. But according to Cern, the SPS is capable of beam energies of 400 Gev. I guess this is also pr nucleon then?
7. ### What does A * Gev/c mean?

I have an exam in introductory nuclear physics coming up in 2 days. I am supposed to present an article which i have already drawn. The article is about heavy ion collisions in the SPS accelerator at CERN. They keep mentioning that the experiment uses Pb + Pb collisions at 158 A*Gev/c beam...
8. ### Electromagnetic potential well, impossible?

Looking at Linear Ion Trap: "or as an actual trap by creating a potential well for the ions along the axis of the electrodes." So it seems that it is possible to create an electromagnetic potential well after all.
9. ### Electromagnetic potential well, impossible?

Well yes, in that article it certainly seems like they are able to make an electrostatic potential well. So it seems to be possible. I wonder why Paul traps are so complicated then.
10. ### Electromagnetic potential well, impossible?

I was having a discussion with my friend the other day. He had just attended a lecture about Paul traps. He told me that the Paul trap potential has a stationary point in the middle, which is a saddle point, and that the 2 pairs of opposite poles are oscillating between being positive and...
11. ### Simple question about vector spaces and bases in QM

Thank your for your answer. I didn't know the equation you wrote in the first paragraph (equality between bases), very enlightening. I had the picture of the vector having a direction and magnitude regardless of base, however i was unable to imagine how you could talk about direction without...
12. ### Simple question about vector spaces and bases in QM

When reading in Griffiths and on Wikipedia about the vector space formulation of wavefunctions, i am constantly faced with the statement that a vector can be expressed in different bases, but that it's still the same vector. However, I'm having a hard time imagining what it is about a vector...
13. ### Induced current in conductor moving circularly in constant B-field

Nevermind i solved it! After reading my last post over, i realized that i should use Faradays law of induction as the more general law, rather than IR=vBl which is a solution to Faradays law in a particular situation. I then obtained the same answer as in the solutions sheet.
14. ### Induced current in conductor moving circularly in constant B-field

Maybe i should add that RI=vBr is derived from Faradays law of induction, stating that the induced EMF is equal to the closed path integral of E+v X B with respect to l (path of the circuit), and Ohm's law stating that the EMF is equal to RI when looking at the entire circuit. I only integrate...
15. ### Induced current in conductor moving circularly in constant B-field

Homework Statement A light bulb with resistance R is attached on a metal rod which is rotating around the point O on the figure. The metal rod is in contact with an electrical conductor which is a part of a circle with radius d. The metal rod and the circular electrical conductor is a closed...
16. ### FLUKEY OR SPOOKY? Incredible real-life coincidences or are they?

I once listened to a song on a cd in a car. When i took out the cd and it automatically switched to radio, the station it tuned to was playing the exact same song and it was on the exact same point in the song as when i stopped it. The song wasn't a very new song, so it didn't get played often.
17. ### Help understanding Laurent series in complex analysis

Thank you very much! i have just found a practice sheet with this problem: Find the Laurent series for the function [itex]f(z)=\ufrac{1}{z(z+2)}[\itex] i'll try to solve this now, thank you again! :)
18. ### Help understanding Laurent series in complex analysis

i see now that all your examples were with singularities in 0, so i guess i can just substitute all your z's with (z-a) in the examples...
19. ### Help understanding Laurent series in complex analysis

This is a very good explanation, thank you! I finally feel like i understand this.. This also gave me a better understanding of the difference between the various types of singularity. Your examples seem to be general Laurent series, they do not include the point a where the singularity is. If...
20. ### Help understanding Laurent series in complex analysis

The part about Laurent series in my Complex Analysis book is somewhat vague and Wikipedia etc. didn't help me much. I am hoping someone would tell me the exact mathematical definition of a Laurent series (around a given point?) of a given function, perhaps providing an example. Also, how can...
21. ### Courses Help Choosing Physics Course: Theoretical vs Experimental Focus

Well i might be able to do both, but i won't be able to do the one i don't choose now until my 3rd year. I have just chosen AM, mainly considering the fact that i will be picking up CS along the way. Thank you for your help!
22. ### Courses Help Choosing Physics Course: Theoretical vs Experimental Focus

Hehe, they have a different interpretation of which courses are necessary, how's that for a BAD pun :P
23. ### Courses Help Choosing Physics Course: Theoretical vs Experimental Focus

Nothing makes me think that. But since we aren't forced to take it, i thought it might only be useful for certain fields or interests. I'm at the university of Copenhagen, they may be doing things differently than most Universities, i don't know.
24. ### Courses Help Choosing Physics Course: Theoretical vs Experimental Focus

Yes that is exactly how I'm feeling, which is why I'm leaning towards AM. But if it was a useless course then i might pick CS.
25. ### Courses Help Choosing Physics Course: Theoretical vs Experimental Focus

I am currently doing classical EM on a high level, and will be taking the next EM course while also taking this AM or CS course. I am very happy to hear an opinion about the importance of AM, since i have absolutely no idea about how useful it is. Thank you, both of you!
26. ### Courses Help Choosing Physics Course: Theoretical vs Experimental Focus

I already know a bit of MATLAB and I'm learning Java. We use MATLAB all the time so i guess it's going to come naturally and i have no problem learning it on my own. But if Analytical Mechanics isn't very useful, then i figured i might as well take the CS course and learn programming now. So i...
27. ### Courses Help Choosing Physics Course: Theoretical vs Experimental Focus

Okay, I am about to finish the first year of my Bachelor in Physics. My hope is to take a Ph.D in Physics (not sure what field yet) and i have not quite yet decided whether i want to focus on theoretical physics or experimental physics, though I'm leaning towards experimental. In about 4...
28. ### Before the big bang the entire universe must have been a black hole.

Thank you! i did know that the big bang was not an explosion of a point or ball, because yes, everything is intuitively and logically wrong about that picture. If you accept that the "inside" of the universe is everything that exists, then logically the big bang is merely an expansion of...
29. ### Before the big bang the entire universe must have been a black hole.

I'm sorry, the wippy article actually says exactly what you just said: "Extrapolation of the expansion of the Universe backwards in time using general relativity yields an infinite density and temperature at a finite time in the past.[32] This singularity signals the breakdown of general...
30. ### Before the big bang the entire universe must have been a black hole.

well since not only all of the matter/energy, but also the space it exists within, was compressed, I don't think it makes any sense calling it a black hole. Black holes occur when a lot of mass is compressed into a tiny region of space, but here we have that space itself is compressed into a...
31. ### Japan Earthquake: Nuclear Plants at Fukushima Daiichi

They certainly are cautious with public announcements. http://www.tepco.co.jp/en/press/corp-com/release/11031225-e.html "Today at approximately 3:36PM, a big quake occurred and there was a big sound around the Unit 1 and white smoke." otherwise known as an explosion... and here...
32. ### The Physics of Sound Waves in Musical Instruments

In short, the sound you hear from a musical instrument is composed of it's ground frequency (f_n), this being the frequency with the largest amplitude, which defines the pitch that you hear, and all of it's harmonics (n*f_n) where n is a whole positive number. For example, if you pick the E...
33. ### Intersection of bars moving at v>c

Reading a little further in the book i found this: "One consequence of SR is that rigid objects can no longer exist, not even as idealized objects. Since keeping an object rigid would imply sending a signal instantaneously." which is basically exactly what all of you said :)
34. ### Intersection of bars moving at v>c

Ah yes, thank you! The reason i ask this is because in the book I'm reading for my SR course it was used as an example on how "movements" can travel at v > c, but movements carrying information cannot. The book used the sweeping of a laser beam across the surface of moon, by a person standing on...
35. ### Intersection of bars moving at v>c

Considering that the bars are very long, so that the time it takes me to accelerate the bar to some speed u, is insignificantly small, compared to the time it takes the light emitted from when i started moving the bar to reach my friend. Wouldn't my "intersection signal" then be able to catch up...
36. ### Intersection of bars moving at v>c

I have two metal bars positioned in space so that, when viewed in the xy-plane, they intersect each other at some point P. One of the rods are parallel with the x-axis and at rest, while i move the other rod downwards, in the -y direction, with a speed u. The speed of the point P, called U_P...
37. ### Energy equivalence between linear and rotational motion

okay, thanks for clearing that up :)
38. ### Energy equivalence between linear and rotational motion

I can imagine that moving the collision point closer to the base of the rod would cause the rod to vibrate or "wobble" more, thus giving it a slower angular velocity, since some energy is lost to this oscillating motion. I was just curious whether or not this loss of kinetic energy was purely...
39. ### Energy equivalence between linear and rotational motion

Thanks Tim, awesome forum by the way ;) I checked the answer to the assignment, and they did use angular momentum/momentum conservation as you said. But the fact that energy isn't conserved here bothers me, since i can't see why it isn't! If we say that no kinetic energy is converted to heat...
40. ### Energy equivalence between linear and rotational motion

whoops, sorry for messing up with the template
41. ### Energy equivalence between linear and rotational motion

Technically this is a homework question because it's from an assignment I'm doing as practice for my exam tomorrow. Imagine a rod standing on a table, the base of the rod is attached to the table with a hinge, so that the rod is able to swing between standing position and parallel with the...
42. ### Math Becoming a mathematician - how important is IQ?

Hey Levis. I am a dane too, and i am currently on my first year of a bachelors degree in physics. I just took my exam in Linear Algebra today (i noticed your remark on how simple vector operations are :) ) and i feel that i can safely tell you, that if you are already this proficient with...