# Search results

• Users: Fr34k
• Order by date
1. ### Gamma matrices

kγ and oν are just arbitrary vectors. I think I kinda get this notation now. As for mathematics behind I couldn't agree more. The problem is we (the students) first saw this kind of notation when actually studying scattering of Dirac particles and didn't really get much (or any) of the...
2. ### Gamma matrices

My bad, you re right it is an expression. I should have said evaluate the expression or simplify or something similar. As for index \nu. Doesn't o =γ\nuo? Would really appreciate some help here.
3. ### Gamma matrices

Homework Statement Solve the equation. What is it's trace? Homework Equations k γμ γ5 o γ\nu γ5 The Attempt at a Solution I don't think this is reduced enough. γμkμγ5γ\nuo\nuγ\nuγ5 trace: just got rid of gamma5 with anticommutation. -Tr[γμkμγ\nuo\nuγ\nu]
4. ### Average velocity of race car

Ah sorry for the confusion I caused, in my language velocity and speed mean the same and I immediately assumed you were talking bout speed. Vocabulary updated :) Yes in this case average velocity is 0.
5. ### Average velocity of race car

What if that 8 times quarter mile circular track would just be 2 mile long straight track? Would average velocity in that case, with your understanding also be 0? What if track is just one big circle, or figure 8? Or some random curve that is connected? I think I know where are you getting...
6. ### Average velocity of race car

8(laps) * 1/4 mile/lap =2 miles This is the distance he traveled, doesn't matter if its circular. 2miles/0.42h=0.833mph This is the average speed. Whole distance divided by time he needed.
7. ### Spectral energy density units

I will just paste the link, cause its faster this way: http://scienceworld.wolfram.com/physics/PlanckLaw.html The last equation for spectral energy density if you look at the units you get eVs/m^3 or Js/m^3, yet energy density is supposed to be J/m^3. What am I missing here?
8. ### Step by step analytical solution of temperature distribution

Done it some time ago but I'll post what I did if someone else will have same problems. The essential thing is to break the partial equation down into sum of components each solving a part of the whole. one for boundary conditions + one laplace for stationary solution + one time dependant...
9. ### Moving charges: Describing its field as photons

The photons are used when you want to describe interactions of particles. Ie. if you have 2 electrons with their own electric fields. "How do they know where and what the other one is"? It's easier for us to imagine that they exchange something that gives both a sense of their surroundings, in...
10. ### Heat generated by particles passing through material

Lets say you have a stream/beam of electrons, you know the current (I), time (t) and all the dimensional characteristics of the beam. You can now calculate the amount of electrons that pass some material in the amount of time. N=\frac{I t}{e_0}, where e0 is elementary charge. Now each...
11. ### Step by step analytical solution of temperature distribution

Homework Statement Lets say we have a 2D rectangular plate with a point heat source and some boundary conditions. I would like to solve and understand step by step the solution to this second order differential equation. Let's say dimensions of rectangular are a and b. 2 opposite sides are at...
12. ### Lidar s-function

Well I am doing some research for school, and many of the papers I've been reading have the same equation and associated graphs with it and it's never explained why exactly in this form. From what I managed to come up with is some sort of attenuation of atmosphere.
13. ### Lidar s-function

Really no one can explain this to me? Anyone know of a good book on the subject (lidar, atmosphere research ...) where this might be explained.
14. ### Why is it that object of more mass attains less velocity

Yes the time would remain the same. If the force is perpendicular to the gravity then the time is the same.
15. ### Why is it that object of more mass attains less velocity

Yes really. Imagine a net x,y,z. and let's say you have 3 rocks. You re at a point (0,0,10) 1st one you drop. Drops at (0,0,0) in some amount of time. 2nd you throw parallel to the x,y grid but only in x direction. So it drops somewhere (x,0,0) in a different time (by your understanding)...
16. ### Why is it that object of more mass attains less velocity

The first ball does cover more distance but in the same amount of time then the second ball. They fall on the ground the same time because there is the same down force on them. The horizontal force is not added to the vertical force. In other words the horizontal force does not magically add to...
17. ### Lidar s-function

What is it, what does it mean/do and why is it used for? Its defined as: S(r)=ln(P(r)r^2/(P(r0)r0^2)), where r is distance in atmosphere and P is intensity of detected light.
18. ### Help understanding how a siphon works?

JaredJames and Drakkith: would you like to enlighten me why am i wrong?
19. ### Help understanding how a siphon works?

http://en.wikipedia.org/wiki/Bernoulli%27s_principle If you would like to understand the physics behind.
20. ### Searching web series

Found it. And it "only" took me 2 days :) If anyone is interested: www.collidingparticles.com cheers, and thanks for help
21. ### Searching web series

If I would I probably wouldn't have to ask on a forum :) But I think it was something to do with CMS experiment at the LHC.
22. ### Searching web series

Hi! A little while back I came across a web series following few physicists around, like a video blog, a documentary movie and I lost the link. Now I can't seem to find it again. Anyone has any clue what I'm talking about? Any recommendations? Thanx
23. ### Physics What field of physics?

Hello! I have the same question as in title, so I didn't want to open a new post. Sorry, barthayn for walking all over your your post. But to answer your question: If you really like physics and you're in it for the money, then I guess your best bet is something with medical physics. Machinery...