Recent content by davon806

So what does M mean? BTW, Reynolds number measures how viscous the flow is ( from https://www.grc.nasa.gov/www/BGH/reynolds.html). "The Mach number is the most important parameter in compressible flow analysis. " (from http://nptel.ac.in/courses/112104118/38). I was just trying to understand...

Homework Statement Hi, The below website states the definition of Mach number, which is a quantity that expresses how compressible a fluid is. https://physics.info/turbulence/ M = sqrt [ ( inertial resistance in the fluid ) / ( compressional resistance in the fluid ) ] = v / c...

For the primed delta in 2nd box, what is delta differentiating with respect to?

Homework Statement Hi there, I was reading a book discussing on the topic of compact Green's function in 2D. However,I have been stuck for a while on some mathematical manipulations depicted below. Homework EquationsThe Attempt at a Solution In 2nd box,I guess the author was trying to pull out...

I am just following my lecturer's note and he didn't say when we are going to use s or t-channel.I apologize but I'm really confused since this is my first course in particle physics, and I have no previous knowledge in QED so that a lot of course notes online are too difficult for me...:sorry...

Homework Statement Hi there, I am a very beginner in particle physics and now I'm struggling with this question. Draw the lowest-order Feynman diagrams for e+e- --> W+W- process Homework EquationsThe Attempt at a Solution There are 3 answers as follows: Q1: 1st pic: Why did the gamma and Z...

Since v = U0cos(wt) and using the substitution v = p/ρ0c0 , rearranging we can solve for p. Then I use eq 1.8.4 with the integrand pv = U0 ^2 cos^2 (ωt) ρ0 c0 .But then the integrand doesn't go like 1/r^2 ,when I integrate over the surface it gives a 4πr^2 term. In addition, I am not sure on...

Homework Statement Hi there, I am a beginner in acoustics and there are severals problems I am currently struggling while I was reading the first chapter of "Theory of Vortex Sound" (available on Google books). Homework Equations For Q4[/B]: The Attempt at a Solution For Q2 and 3, as...

Thanks I got the first part of red box:smile:. For the remaining part, I need to show that the Hamiltonian is degenerate. By definition that means E corresponds to more than 1 eigenstate. I am not sure , but from the form of eigenstate | E,m > and the equation H | E,m > = E | E,m > , we see...

1.I don't know what Π_1 is representing , I mean,like position and momentum operator you have Xψ = xψ , Pψ = -ih d/dx ψ ,but here you have got something like ΠXΠ^-1 = -X which is not the usual form of Kψ = kψ. Then what can I do to compute [ H,Π } ? 2.Since L_3 is acting in the z-direction, Π...

Homework Statement The red box only Homework EquationsThe Attempt at a Solution I suppose we have to show L_3 (Π_1) | E,m> = λ (Π_1) | E,m> and H (Π_1) | E,m> = μ (Π_1) | E,m> And I guess there is something to do with the formula given? But they are in x_1 direction so what did they have...

Thanks, after expanding the exponential I recover the minus sign:smile:.

Homework Statement Homework EquationsThe Attempt at a Solution 1.1st circle on the left : where did I miss a minus sign? 2. How to show that the last term is equal to 1? Thanks!

Homework Statement Homework EquationsThe Attempt at a Solution It is a short question so I don't suppose it is difficult. However, I don't really understand what it is asking for : 1.The TDSE itself is already a 2nd-order differential equation (if you substitute the terms back into H). 2...

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