41,469 reputation
356134
bio website inspirehep.net/…
location Duchy of Grand Fenwick
age 44
visits member for 4 years, 8 months
seen 1 hour 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.


Jul
28
comment Does an ice cube change its core temperature as it melts?
@Frisbee Certainly not the question from the text, but in general the things we tell introductory students can leave them with an incorrect impression about the question in the title.
Jul
28
comment Does an ice cube change its core temperature as it melts?
Concerning the units, see meta.physics.stackexchange.com/questions/15/…. This site is run by people in the US and hosted in the US, but I doubt very strongly that the Stack Exchange team would want to have the network considered as being US centric. It's a big internet out there.
Jul
27
comment Does an ice cube change its core temperature as it melts?
To answer this question exactly, one needs to know how quickly heat is being transferred to the subject. The rules that are generally taught in an introductory course contains the (sometimes hidden) assumption that the heat transfers slowly compared to the time needed for conduction throughout the system.
Jul
27
comment Is momentum an invariant?
This is in no way related to the meaning of the word "invariant" used by relativists.
Jul
27
comment Speed of the train is faster than a car, why?
Er ... one is going faster than the other? Beyond that it is engineering and policy and human performance limits and costs issues, none of which are physics.
Jul
27
comment Is momentum an invariant?
If the nature of the quantity is not clear in you personal, look-how-much-of-a-purist-I-am-I-write-move-complicated-notation-than-you-do way of writing things, then perhaps you should reconsider. Seriously, with as much effort as you put into writing things you have managed to obscure whether you mean the 3-vector, the 4-vector, the magnitude of the 3-vector or the magnitude of the 4-vector. Only one of which invariant, and that is properly called the mass.
Jul
27
comment What do light wave oscillations look like?
physics.stackexchange.com/questions/160042/… physics.stackexchange.com/questions/192365/…? physics.stackexchange.com/questions/163298/…? and I know there were more.
Jul
27
comment Optics phenomenon with my glasses?
Another search term of interest is "chromatic aberration".
Jul
27
comment Inelastic cross section derivation
"The author simply assumes $\vec{p}_1=−\vec{p}_2$ for the momentum of the particles after collision" This still for a two-particle final state and evaluated in the intial-state CoM frame? If so, think a little on the matter. It should be pretty clear, why.
Jul
27
comment Why is the equation for electric potential energy so counter-intuitive?
physics.stackexchange.com/questions/6074/… physics.stackexchange.com/questions/35878/…
Jul
27
comment Find tf and end distance
Note that despite @Acid's comment showing your work is not enough. Please read the link in the close explanation before posting further questions. You have to extract the physics that is troubling you from it's context in a particular problem.
Jul
27
comment How many of the Standard Model free parameters are mutually independent: (all of them)?
Numerology at its finest. This "Replace the √ћG with 4πn where n has the right dimensionality." alone makes that clear: it's a completely arbitrary step for which you have no motivation besides getting to the "right" value later on. Later on you move the $4\pi$ to the denominator.
Jul
27
comment How is this possible that photons are absorbed?
Related (some possibly duplicates): physics.stackexchange.com/q/59213 physics.stackexchange.com/q/167787 physics.stackexchange.com/q/76272 physics.stackexchange.com/q/193133
Jul
27
comment Why is the equation for electric potential energy so counter-intuitive?
Note that you are comparing a "for use in limited circumstance (i.e. small motions near the surface of the some large mass) version of the gravitation rule to a general version of the rule for electrostatics. Of course the simplified case is simpler than the general case.
Jul
27
comment Do atoms behave like waves?
See the question I linked above for links to doing it with $\mathrm{C}_{60}$ and $\mathrm{C}_{70}$ buckyballs.
Jul
27
comment Do atoms behave like waves?
Related: physics.stackexchange.com/q/131714
Jul
26
comment Can the electric potential corresponding to the negative plate ever be equal to anything bigger than zero?
The point is that there isn't a single well defined value. You really are free to pick the value of potential for one point, and all other are then computed relative your choice. As with gravitational potential problems there are some customary choices. Can you guess what one of the customs is? But what happens to that custom when you introduce two [batteries|capacitors|other things with a "negative plate"]?
Jul
26
comment Can the electric potential corresponding to the negative plate ever be equal to anything bigger than zero?
The zero of potential is arbitrary...
Jul
26
comment Is light moving because of self induction?
No problem. The classical waves taught at the intro level are linearly polarized because the source has a simple, linear oscillation. But that's not a problem from a quantum POV because the linearly polarized states are also eigenstates of the free hamiltonian, and they are related to the circularly polarized stated by a simple linear combination in both classical and quantum views. Cute, eh?
Jul
26
comment How can I obtain a unit vector of a shifted spherical system?
Consider the transformation that took the system from sphere-at-origin to sphere-not-at-origin (i.e. $z' \leftarrow z-2R$). Now consider the reverse transformation...