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  • 21 votes cast
Dec
27
awarded  Scholar
Dec
27
accepted With radian as a unit, should action and angular momentum have the different units?
Dec
27
comment With radian as a unit, should action and angular momentum have the different units?
Thanks for the answer. Reading many different opinions elsewhere and doing some algebra I got to the conclusion that radian in some sense tags pseudo-quantities (like pseudo-vectors and pseudo-scalars), which I think makes clear what would be the role. The problem is that opens another Pandora's box because that also means that to be consistent $\mathrm{rad^2} = 1$ which still makes it special if we force it as a dimensions. So, for different reasons, I start to agree with your statement "However, that distinction cannot be usefully maintained in more complicated calculations"
Dec
27
awarded  Commentator
Dec
27
comment Unit of torque with radians?
...although I am getting to the conclusion that in a consistent radian system $\mathrm{rad^2} = 1$ and $\mathrm{rad} = 1/\math{rad}$. In the same way that the product of two pseudovectors is a vector.
Dec
27
comment Unit of torque with radians?
Actually, the result in your example is $m/s$ no matter what. The reason is that $\vec v = \vec\omega \times \vec r$ and the $\times$ operation is the one that eliminates the radian units.
Dec
27
comment Unit of torque with radians?
Actually the unit of angular momentum, using radias is $\mathrm{kg\cdot m^2/s/rad}$.
Dec
27
comment Unit of torque with radians?
In some sense the unit "rad" gives the information that the quantity is a pseudovector. It is "generated" by the $\times$ operation.
Dec
26
comment With radian as a unit, should action and angular momentum have the different units?
There is an opinion about this from a units library: boost.org/doc/libs/1_56_0/doc/html/boost_units/… I agree with it but I also see that to be consistent also requires hbar to have different units than h.
Dec
25
asked With radian as a unit, should action and angular momentum have the different units?
Nov
10
awarded  Critic
Nov
25
comment How to rebut denials of the existence of photons?
A more concrete question to pose would be whether the EM fields are quantized or not. (Let alone, that a theory with quantized electrons and not quantized EM fields would be difficult to state consistently)
Aug
4
comment Is a Perfect/Lossless Mirror possible?
Note that even if intensity is preserved, there will be loss of phase-information. An essential quality of a mirror is that it preserves phase so you can do for example a diffraction experiment.
Jun
25
comment Will a relativistic rocket be destroyed by incident photons?
Fast atoms will not necessary do any damage. Since they go fast the damage that they can produce in a given material thickness will be negligible. Am I missing something? For example, en.wikipedia.org/wiki/Stopping_power_%28particle_radiation%29
Apr
3
revised Phonon carries zero spin. Why?
added 77 characters in body
Mar
31
answered Phonon carries zero spin. Why?
Dec
17
awarded  Student
Dec
17
comment Name for thermodynamic derivative $dP/dT|_V$?
@NickKidman, thank you, yes simply related quantities, including dimensionless, with given names, are also welcomed. I added that to the question.
Dec
17
awarded  Editor
Dec
17
revised Name for thermodynamic derivative $dP/dT|_V$?
example for related quantities