I am a course instructor. In my courses, which are now online due to the pandemic, I have optional live sessions. In those live sessions, I give examples of how to solve problems (it's a math-based course), and answer student questions in a group setting.
This design comes as close as possible to...
> I think that if I were to provide recordings of these live sessions, more students would not bother to attend. I strongly believe that attendance at these sessions is pivotal for understanding, and that watching posted videos of these sessions will not have the same effect...I specifically do not want to allow this, as I think it discourages proper time management and may lead to problems down the road.
Ugh, I hate this
why is it so hard to accept that attendance != understanding
Both definitions are fine as long as you're careful with signs.
Here's a derivation of your gravitational potential energy using the idea of the negative work done "by the field." (Note the initial negative sign.)
$$U(r)=-W_\text{by field}=-\int\vec{F}_\text{field}\cdot d\vec{s}=-\int_{r=\inft...
What does the initial negative sign stand for? Is it because the work done by gravity is positive and the change in potential energy is negative? And vice versa the external agent?
Sanity check: can I say that the renormalisation group equation (for the vacuum polarisation in QED) arises because the potential at some momentum should be independent of the arbitrary reference scale $p_0$ at which the renormalised electron charge is defined?
$p_0^2 \frac{d}{dp_0^2} \tilde{V}(p^2) = 0$ is the RGE
@satan29 $J=sE$ is the formula for the current density produced by an external electric field applied to a material of conductivity $s$
i.e. the source of the field is not inside the material, and hence $\nabla \cdot E_\text{ext} \sim \rho = 0$
but that $\rho$ is not about all charge inside the region we're looking at, it's just about the charge responsible for this external field $E_\text{ext}$
I am trying to get familiar with the concept of corepresentations of magnetic groups. My question is what happens in the case where the magnetic group is unitary, hence, lacking time reversal symmetry. Do we still use the notion of corepresentations, is it the same as the irreps? I don't know how to construct them, or if they have any physical significance
yeah, they mostly don't even bother to give you anything resembling proper directions in dialogue so you have no choice but to follow the blinking light
You probably want to do this with 3j coefficients, since spherical harmonics form a basis the product of two of them is a linear combination of spherical harmonics which can be expressed in terms of 3j's, then integrating against the third leaves one remaining coefficient which involves one kind of 3j
Also yes, there's always a smaller (or larger, depending on your sign conventions) proper time between two points, since you can always connect two causal points via a sequence of null curves
So there's always a causal curve of length 0
But beware of saying that this approximate the curve, since they have different properties
I want to see how the ball in this question would move
A small ball is suspended from a point O by a light thread of length l. Then the ball is drawn aside so that the thread deviates through an angle θ from the vertical and set in motion in a horizontal direction at right angles to the vertical plane in which the thread is located. The initial velocity that has to be imparted to the ball so that it could deviate through the maximum angle 2 π in the process of motion is v 0 = cosθ xgl
So this is pretty stupid and niche, and possibly not interesting to anyone here, but I'm pumped about it. I spent the last several months trying to change one of my guitar hero guitars into a left handed one by basically ripping up the front of it and swapping all the plastic around. I made some bad design calls which led to more soldering than needed, which led to me breaking more wires, which led to more soldering. I thought it was basically toast, but I actually got it working today.
So I'm pretty amped that a stupid project that snowballed out of control actually got finished.
I get really into stupid projects like that too. The funny thing is, I was so used to the right handed version that I keep reaching to the wrong place for the whammy bar that I swapped to the correct place for lefties.
Symmetry
First, the apple appears to break into 3 parts, not two. Second, the break is obviously not as "clean as a knife" if you slow the video down and watch it carefully. However, the break is much cleaner than if you tried to tear the apple into chunks with your bare hands (unless you happe...
Someone should introduce this guy to Bob Mortimer.
Both definitions are fine as long as you're careful with signs.
Here's a derivation of your gravitational potential energy using the idea of the negative work done "by the field." (Note the initial negative sign.)
$$U(r)=-W_\text{by field}=-\int\vec{F}_\text{field}\cdot d\vec{s}=-\int_{r=\inft...
Symmetry
First, the apple appears to break into 3 parts, not two. Second, the break is obviously not as "clean as a knife" if you slow the video down and watch it carefully. However, the break is much cleaner than if you tried to tear the apple into chunks with your bare hands (unless you happe...
