40,920 reputation
356130
bio website inspirehep.net/…
location Duchy of Grand Fenwick
age 44
visits member for 4 years, 7 months
seen 54 mins ago

Experimental nuclear and particle physicist. These days I'm teaching, but I've spent a lot of time on nucleon structure in fixed target electron scattering and neutrino oscillations using reactors and beam sources.

Been reading Zemansky & Dittman's book on thermodynamics recently. Quote: ``The concept of temperature is rich in interpretations and levels of abstraction.'' Nice.


5h
comment Why is pressure in a liquid the same in all directions?
The question explicitly acknowledges that this is accepted position and ask for an explanation of why the OP's mental model is faulty. This answer completely fails to address the question.
5h
comment What is time and time dilation?
"so we can converse." As an aside, Stack Exchange is intentionally engineered to not be a discussion forum. The chat system works OK for that, but you need a minimum rep to be an active user.
6h
revised What is time and time dilation?
edited tags
6h
comment What is time and time dilation?
A couple of comment may that may help you in your interaction with Physics. First, this is neither a homework help site nor a learning physics resource. You can get some help in those direction but you have to play by our rules. Second, we get some version of this question every single week. Often every day. We're sick of it. Seriously. This is one you should be using the site search and other resources for. Asking a question that every single student of physics (every one!) has at some point in their studies suggest a lack of care for our time and energy.
8h
answered “X-rays”, “gamma rays”, “sun rays”… But electromagnetic waves are NOT rays and DO NOT consist of rays?
8h
comment How can laser interferomerty be used to measure path difference smaller than wavelength of laser light?
The question isn't "Can this be done?" it is "How can this be done?".
8h
comment Are differences between elements besides the number of valence electrons negligible in forming matter and giving certain properties?
Far too strongly stated, and while the question is more or less OK for physics it would have been a natural for Chemistry.
9h
comment Why charge density is higher in the sharp edges of conductor?
Also: physics.stackexchange.com/questions/103048/… physics.stackexchange.com/questions/188226/…
9h
comment What is wrong with this theory? - This is a unique way to visualize the universe
Two things. (A) Keep it civil. (B) What Kyle said: this is not the place to promote, test, publicize, or hone personal theories. It is not what we do here.
21h
comment Is the wobbly rope depiction of a radio wave inherently wrong? And how do vectors of parallel waves align with each other?
The wave doesn't have a spacial form. Really it doesn't. The analogy to displacement waves in matter simply fails you there.
21h
comment Is the wobbly rope depiction of a radio wave inherently wrong? And how do vectors of parallel waves align with each other?
"Can you answer my second question (whether a spatial radio wave is uniform or sinusoidal in a direction perpendicular to its propagation direction)?" Depends. At distances very far from the transmitter there will be effectively uniform across the face of the wave front.
21h
comment Is the wobbly rope depiction of a radio wave inherently wrong? And how do vectors of parallel waves align with each other?
On close inspection I find where you've written "Distance and "strength" are different things and don't correspond with each other!" That explains a lot. There is, in general, no expectation that the different axes of a graph will be of the same kind. WE plot position against time and velocity against time and electric field strength against magnetic field strength against position, and so on and so forth. The preparer of the diagram is suppose to label these things and you are suppose to read the labels. Alas, most of the diagrams you've exhibited are not labeled.
21h
comment Is the wobbly rope depiction of a radio wave inherently wrong? And how do vectors of parallel waves align with each other?
You do actually find visualization like the ones that you are trying to draw at the bottom, but usually in the form of videos so you can see the time dependence. But people show them, explain them and then revert to using the one ray diagram because the full 4D visualization is too complex to indicate anything else on.
21h
comment Is the wobbly rope depiction of a radio wave inherently wrong? And how do vectors of parallel waves align with each other?
It's not a analogy to "the form" of a light wave, it's a visualization. A map. A tool on which we can draw. And the map is never the same as the territory and you have to learn to read them: to understand the symbolism and that there are things left as understood. In any case, light waves don't have "a form", they are temporary, passing distortions in a field.
21h
comment Is the wobbly rope depiction of a radio wave inherently wrong? And how do vectors of parallel waves align with each other?
What is wrong is not the depiction but the interpretation you insist on putting on it. No serious description of EM waves ever used ropes or strings as anything but an analogy. You seriously have to learn to look at that picture and think "field strength" not "a bit of matter moving out of line".
1d
comment Is a non reflective display possible?
The fundamental problem with this as an answer is that we don't have any trouble defining things that can't be. Indeed most of first year physics is built on the assumption of objects which have properties that we know no real object can actually have (consider all the massless inextensible strings and the frictionless pulleys and the rigid semi-infinite rods).
1d
comment Using the equations $y(x,t)=A\sin(kx-wt)$ and $w=2\pi f$, if we solve for amplitude could we determine a relationship between amplitude and frequency?
Your text is almost certainly using a lower-case omega ($\omega$) not a latin double-u ($w$) for the angular frequency.
1d
comment What is the kinetic energy of a proton as it is falling towards the core of the star?
Note that the (or at least a) proper way to indicate scientific notation in LaTeX math-mode is 1.33 \times 10^{-11}. Also, units should be typeset in upright text and preceded by a thin space. One way is to use \,\mathrm{J}. All together that looks like $1.33 \times 10^{-11}\,\mathrm{J}$.
1d
answered Can two artificial bodies be built in space and be made to orbit each other?
1d
answered How to know if a body is travelling with uniform acceleration or not?