Recent content by peterpang1994

As the geodesic equation in a form of is quite familiar for me. But I still cannot derive it in terms of time coordinate parameter; I can't get the second term on the right hand side what I can get is ½{d[lngαβ(dxα/dt)(dxβ/dt)]/dt}dxμ/dt How can I obtain that term?

Homework Statement Given a vector field F=-y/(x^2+y^2) i +x/(x^2 +y^2) Calculate the curl of it the line integral of it in a unit circle centered at O Homework Equations The Attempt at a Solution I calculated that the curl is 0 but the line integral is 2π. I don't think this...

Push!

Homework Statement 2 point mass M1 and M2 . Their separation is r0. They are released at rest at t=0. Find the time of collision (T)of them due to gravitational attraction in terms of M1, M2 , G and r0. Homework Equations F=ma ∫a(dt)2 = s (a is acceleration, s is displacement) x0=(M2/(M1 +...

thank you very much. Is that the operator you suggested in only focused on the electron in a hydrogen atom? And I am still having problems on the total orbital angular momentum and the total spin.

Recently, I read an article about spin and polarization (http://www.mathpages.com/rr/s9-04/9-04.htm) , but I don't understand how the spin operator defined, can anyone give so help? any help would be great!

thx a lot

Recently, I read a article talking about the average paths of single photons in a double-slit experiment(http://scienceblogs.com/principles/2011/06/watching_photons_interfere_obs.php ). And I am a little bit confused with this experiment and the concept of Feynman's formulation of quantum...

I learn calculus in school as well. But I don't think that my mathematical knowledge is enough. :confused: For vectors, I only know the basic vectors properties. For the vector calculus, I know the definitions of gradient and divergence. But the applications of them ...

Thank you very much! That would be very helpful!

any suggestions for physics books ?? I am a high school student studying physics,I am very interested in physics. Since my teacher is teaching very very slowly, I have finished most of the books in the syllabus. I want to explore more on physics. Could you show me the way? Is there any...

I have tried to calculate, and I assume that the train is traveling along a straight line and B flash a light when B passes A. If you consider the speed of the bullet, the distance between C and A, the distance between D and A, you will find that A must die. P.S. The train is traveling with...

Thank you very much .In the case of bicycles, how should I consider the net moment acting on the bicycle if I choose the point where the friction and the normal reaction acting on.

Re:dx Can I summarise the content you written in one simple sentence. The instruments which is used to "measure" the quantum phenomenon would take part into it and follows the uncertainty principle. Is that a correct description??

But when I choose the other point as rotational centre and chage the moment of inertia by parallel axis therom, there are probabilities for the rod to rotate or not.