I'm reading something which highlights the Feynman rules for QED, and it talks about what happens if you go along a fermionic line. For example this picture:
http://wikipremed.com/image_science_archive_68/010601_68/170750_298px-ComptonScattering-u.svg_68.jpg
According to these notes, there...
I just entered graduate school. As an undergraduate I took a graduate course in Quantum Mechanics, mostly for fun and practice because I knew the credits wouldn't transfer to the uni I was applying to for grad school.
So, I got accepted there and even though the credit wasn't transferred the...
Homework Statement
I'm learning QFT and trying to do a basic problem finding the equations of motion from the Euler-Lagrange equation given a lagrangian.
The lagrangian is in terms of:
F_{\mu\nu}=\partial_{\mu}A_{\nu}-\partial_{\nu}A_{\mu}
so then my issue comes in with this part of the...
Wow I didn't know it would be that simple.
I was thinking that a_{CM} would be less than the total force over mass because some of it would go into causing angular acceleration.
Thanks for the explanation ehild.
Homework Statement
I'm just reading a graduate level mechanics book for enjoyment/practice and I just need a push in the right direction with one of the problems.
It has a cylinder that is wrapped with a string around the circular part. The string is then pulled (so the force is tangential...
The hard part is realizing that the speed the wheel is moving at (I'm assuming it's a wheel attached to a moving body like a car driving on the road) is equal to the tangential speed of a particle on the end of the wheel. Same can be said about acceleration.
So, then you simply convert...
Sorry I didn't notice you responded sooner, for some reason it didn't notify me.
But "one wave" should be measured from bright spot to bright spot.
Or if you prefer, you can go from dark spot to dark spot. That might seem more intuitive since you are including the entire bright region.
Well it's not as simple as just counting bright or dark fringes.
Because an entire wavelength includes both, so in your picture you actually have a fractional amount of wavelengths.
Unless you want to estimate that there are 6.9 wavelengths or something like that then the best thing to do...
I was about to bring this up.
I love what google does. Maybe I'm wrong, but I do not get the "money hungry" vibe from google even one tiny bit.
Everything google is involved in is either fully supported by me or something that I just don't care for.
They don't have anything that I am...
Well something is definitely wrong.
Either it is an error in the book, or a very poorly worded question that both of us are just misunderstanding somehow.. (although it seems pretty clear).
If the graph showed the entire trajectory it should continue going down to -30m/s
There is just a lot of...
Right, but what I was asking is if you mistyped/misunderstood the question,
not the answer.
There are 3 parts to your original post: question, graph, books answer.
2 of them work with each other, the graph and the books answer
the thing that doesn't fit with those two is the question.
So I...
The whole question and solution seems a bit odd to me.
First because if the object fell back to its starting point then the graph should go down to -30m/s, but instead the graph shows it as stopping at -10m/s, I was assuming that it just went below the graph but they just don't show it, but...
You got P as a constant because you treated it like one when you took the integral.
But if you look at the ideal gas law you can see that pressure is a function of volume. So then you can put that expression into the integral and n, R, and T are constants, then integrate.
I don't see a_t in your pic.
But anyway, I am pretty sure that the tangential direction is the theta direction as well.
So a_theta = a_t
In polar coordinates the radial direction is out from the origin, and the theta direction is perpendicular to that, which would be the tangential direction.
Homework Statement
The entire problem is quite in depth. But what I am having trouble with is just a small part of it, and it boils down to finding the following commutator:
\left[ S_{z}^{n},S_{y}\right]
where S_{z} and S_{y} are the quantum mechanical spin matrices.
The reason is that I have...