# Search results

1. ### Equation to relate voltage to distance of a spark

I need to calculate the minimum distance for which a charge of some voltage will jump. Is there any equation that relates distance of a spark jump to voltage (a fairly generalised equation will do, I don't need to worry about strange shapes of the charged bodies that the charge leaps between or...
2. ### Frictionless sphere, falling particle

Thanks, I got it now, the angle is the arccos of 2/3. I just used conservation of energy for the particle, and get mgh+mv^2/r =mgh+mv^2/r, then solved fo V^2 later by equating centripetal force with mgcos(x) so the net force would be 0, where the particle fell off of the sphere.
3. ### Frictionless sphere, falling particle

Homework Statement A particle initially sits on top of a large smooth sphere of radius R. The particle begins to slide down the sphere without friction. At what angle . does the particle lose contact with the sphere? Homework Equations g=9.8m/s2 perhaps? (Is this dependent on the...
4. ### Spring and falling body problem

1. Neglect air resistance. A suspention bridge spand the colorado river at a height of 321 meters. Consider a 75kg bungee jumper, and a 200m bungee cord which obeys hooke's law (once it reaches its unstreched length). a) calculate the spring constant k, so that the jumper halts just above...
5. ### Astrophysicist salary

Professor I am going to be an entering freshman in the field of astrophysics this coming year, personally, the reason that I find astrophysics to be both fun and fiscally sound as a decision, is because I plan to move out of the country, where physicians are payed significantly less (France...
6. ### Im thinking about building a cyclometer

Should i be able to replace those large stationary "dee" magnets with electromagntes? (or would that be a grand misuse of the powersupply, as i know i will need to supply an ample amount to the electron gun, and the current which i need to accelerate the particles, rather than simply keep them...
7. ### Getting a solution that contains 40% iodine

you should really attepmt the problem before posting here.. but- okay... how many litres of the 80% stuff is there.. that's the limiting, otherwise you might as well use 25 litres of it diluted with water to 50 litres or if you can't dilute with distilled water, like any reasonable...
8. ### Speed of an arrow from a bow

im not exactly an expert, but it seems to me like air ressistance and friction won't be flawing any simpler calcuations too greatly when your talking about the initial velocity, i wouldent even bother with them, mabye again that's because i can't exactly follow your equation, explain how you...
9. ### Proton current

i was thinking over how a hydrogen fuel cell works, seperating the electrons and protons (into its ions like any other way of converting electrical energy to chemical) but i wondered if the protons as well as the electrons could be used as a current to creat a circuit such as the electrons do...
10. ### Forces affecting the path of a photon

the electromagnetic force would not affect the photons, because they are not charged, i see that much now, i also see that the splitting which may or may not happen would have an affect on the path of the photon, and perhaps lead to the separation of it temporarily, but as another question...
11. ### Forces affecting the path of a photon

could anyone be so kind as to provide a list for me, I am attempting to better a formulate a further question, but this list would be greatly helpful in my understandign of what i am trying to ask. the two i can easily think of are: 1.gravity 2.magnetism can anyone correct me if either...
12. ### Energy and gravity

in energy directly related to gravity as mass is, it seems that it should be according to relativity, but this leads me to the question of why dark matter need be proposed to explain the differences in gravity and mass proportionality of galaxy clusters and such. Is this difference not as simply...
13. ### Riddle game - Something for you scientists

so ehh.. how do i go about putting the answer the the impaler bit in... (the impaled inhabitants of i can't remember what city) I've tried all sorts of stuff... dead, impaled, corpses, bodies, undead all with and without the infront. nevermind that... i got it, i was thinking of the...
14. ### Ac vs dc power

which does an appliance sich as a ipod run off of..? i know verry little of such things =(
15. ### Medical Accelerating learning

I myself am in 10th grade in a public school, i had perviously been in a private school, and a separate (full time) gifted schooling program. In school i have skipped two years of math (the only one to do so in 3+ years) as well as having skipped honors chem beofre taking ap chem a year before...
16. ### How is mechanical energy converted to electrical

I love wikipedia. It is the answer to all questions. edit:( i found wikipedia usefull)
17. ### Is Time Travel Impossible?

:frown: uhh buddy... there are a great number of dimensions even beyond the fourth, or atleast they are just as easily accounted for as the first three you accept, and therefore cannot be refuted without some evidence against the existence of them.
18. ### Is Time Travel Impossible?

uhh.. these "recent advances in theoretical physics are not near as recent as you suggest" also the paradox your referring to is known as the grandfather paradox, and is quite well known. also your reference to the "quantum world" seems to me to be no more descriptive of the region you are...
19. ### Mass in things like gluon fields

what sort of equations are specific to this, and could they be explained for me? I am jumping from one place tot he next in my learning of these sort of things, as i have honestly never taken a physics class. i still have a fairly in depth knowledge of the relativity, lorentz's ideas of it, some...
20. ### Perpetual Motion

curious... but how did you go about this project... and perpetual motion in anyhting other than a thought project is... not reasonably expected to occour, and it does not. you probably used some sort of magnets in an electric motor type scheme did you not? this may eventually rub down on the...
21. ### Biology related science fair ideas?

thanks, exactly where i should have looked.
22. ### Biology related science fair ideas?

i know there is a big link for science fair ideas somewhere, i cannot seem to find i though, could someone redirect me at the least, or perhaps post your own ideas here?
23. ### Good textbook

anyone know of a good quantum physics textbook?
24. ### Equationins governing QM

thanks meir also, taking me a bit to piece togther the tex, i don't use it a ton but it gives me an ida of what to look for.
25. ### Intermediate qm what should i know

thank you greatly kruger, and on the note of dexter, what sort of math is then involved in qm...i would assume some sort of linear algebra would be the basis.
26. ### Intermediate qm what should i know

i eventually wish to learn all that i possibly can, though atm i have only recently bothered with qm much at all. I have a near complete as i can get understanding of Relativity, have read the origional papers by lorentz, einstein, and the like...so if you wish to base any comments on that view...
27. ### Equationins governing QM

firstly, I am deeply astounded at my typing job in the title.. what are the main equations governing qm, I am sure that atleast a few must exist, though i fail to turn them up in any place i look. To aim you more toward what i seek in particular should I be plesently surprised with a plethora...
28. ### What is a Black Hole Actually Made Of?

correct me if I am wrong, but here is what i have to say on the topic: the event horizon of the black hole is a great deal larger than its singularity (if this is the sort of black holes we choose to discuss) the singularity is that point at which the gravitational pull of the former, more...
29. ### Lorentz' ether

carl thanks your were quite helpfull.. dident realize i was dealing with a whole different relativity...foolish
30. ### Lorentz' ether

Lorentz' "ether" I have recently read a paper written by H.A. Lorentz in which he repeatedly referred to an "ether"... what seems strange to me is i am not sure what this ether is, and it is only described as how it can manipulated mathmatically. It has appeared in more than one of his...
31. ### EFEs in context

thanks... and if anyone isent tired of answering ym wuestions yet, could someone confirm that a lorentz-4 four vector as mentioned above can also be called a reiman curvature tensor (I'm more familiar witht his term)
32. ### EFEs in context

ha! I see a reiman tensor explains 4 dimensional space... and is why it is used in the field equations.. I also understand the meaning of when you earlier stated that a rank 3 tensor was a vector as was a rank 1 tensor. and the metric tensor being a dot product... my only question is... is a...
33. ### EFEs in context

wow you guys are helpfull... and I know of the lorentz transformation, i have used it in thought expirements to calculate time deviation between an observer and the (observee? i guess) , so was i putting this to incorrect use when i tried to plug in some made up velocities and solved for...
34. ### EFEs in context

well I am 15 now :P 16 in march :) also- a tensor is a triple vector? - or a three dimensional vector (triple probably not the right word)
35. ### EFEs in context

actually i finally ordered that dover book, the forward by lorentz to go with it grabbed me completely... and only \$9
36. ### Photon splitting

thanks both- pallidins footnote helped me put this to a more specific image
37. ### Photon splitting

photon "splitting" I have heard a thing or two about photons splitting into more photons and dividing the origional energy amongst themselves, but have never really heard it explained. I suppose it should work out just fine with photons having no mass, but just te be sure, is there some...
38. ### EFEs in context

i have read gravitation, tanks i will look at the other recomendations (the last looks like what I am looking for)- and ohh drat dident realize what thread i was in, i hope some more poeple find this (qm is atleast related so probably..) - and ohh yes i began my learning of general...
39. ### EFEs in context

could soemone give me a site, or let me know of a book that gives the field equations in the context which Einstein presented them, along with his discussion of their implications?
40. ### Zumdahl text users

:) well that's an opinion..but it worked for him dident it?
41. ### Importance of enthelpy

ohh.. duh its just a simplification (or an attempt therof) to help in the finding of volume or pressure or one of the other described variables.. as allways, thanks
42. ### Zumdahl text users

yeah it is pretty good as far as i have seen
43. ### Contact Lenses

there is potetial damage due to oxygen restriction, but this depends on the typ of contact as well as duration of use (soft lenses will work better) though generally its not a great idea to do this daily, and especially not to sleep in them, as some soft lenses allow when worn without another...
44. ### Importance of enthelpy

i understand enthalpy, what it is, how it changes. I have only two questions... first, as enthalpy changes the Pressure can change also (i know it doesent have to, but my book seems to be attempting to tell me that it never changes) and secondly could someone present a problem in which enthalpy...
45. ### Zumdahl text users

Main Question: How many people are taking a course using a zumdahl text? I ask this because i would like to add a few people as buddies if they don't mind, and will help them with the class as i go through it, to help keep my memory fresh.
46. ### Quick question!

polar -ionic go togther, so do polar and polar...and finally nonpolar/nonpolar (remember the catchy jingle like dissolves like) ok so mabye there is no catchy jingle, but yes that would seem to be correct (assuming cyclohexane is nonpolar since i dident actually look it up)
47. ### I ! soap is too complex

i would like to take a shot... what are they? either post (this way more people could exmine them) if if you wish to pm me-go for it
48. ### Transformations of functions

what I've atleast been told, ad seems to be a fairly easy way to look at it is to call all the x values in the equation y, then all the y values x ( f(x) for ex would be y.. the changed to x ) first of all, then to solve for y - : the first part i allways found confuzing, and useless at best...