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"head" in the name refers to the Mathematica concept. That was the first account I created. I kept the name.


2d
answered Confusion with anti-symmetric tensors!
2d
comment Confusion with anti-symmetric tensors!
It's not obvious to me that the definition you give is correct. Do you have a reference? Usually I see it defined without the factor of $i$.
2d
comment Confusion with anti-symmetric tensors!
why is there an "of couse" before your definition of the dual tensor?
Dec
16
comment Difficult Atwood's machine problem - Finding $L(t)$
I see. So the last equation is really a differential equation $\frac{d \theta}{dt} = K \sqrt{\theta^2 - \theta_1^2}$. Do you know how to solve differential equations by separation of variables?
Dec
16
comment Difficult Atwood's machine problem - Finding $L(t)$
So $\theta_2=\theta_1 + 2\theta$?
Dec
16
comment Difficult Atwood's machine problem - Finding $L(t)$
In your last equation, what is the difference between $\theta$, $\theta_1$, and $\theta_2$?
Dec
14
awarded  Revival
Dec
14
answered Does a tire need to slip to generate force?
Dec
11
comment Does the effect change if a continuing and constant force acts upon a mass?
Yes, becuase $P=Fv$ and $v$ is increasing. Also you can see the power from the change in potential energy. The potential energy is $mgh$, so if we view this as an energy source, it is being used up at a rate $mgv$, which is increasing as $v$ increases. So the constant $F$ is not being generated by constant power, but by an increasing power, as stated in my answer.
Dec
11
answered Does the effect change if a continuing and constant force acts upon a mass?
Dec
11
answered Determine coordinate system for rotating wheel
Dec
9
answered Why does an unhinged body rotate about its centre of mass?
Dec
8
comment Change in energy ideal gas
What is $T$ on the right hand side? Also, where did your second term on the right hand side come from?
Dec
8
comment Speed of an electromagnetic soliton in free space
I should say that I had the 1-d wave equation in mind, as you show in your gif. I am not sure what localized travelling wave solutions look like in 3d.
Dec
8
answered Speed of an electromagnetic soliton in free space
Dec
8
comment Why is surface tension parallel to the interface?
No, surface tension always acts.
Dec
8
comment Proof of Kohn's theorem
I will try to narrow in on your confusion. Which of the following two things are you confused about, 1, 2 or both? 1: In the interacting case, $\dfrac{i}{\hbar} [H , \mathbf{P}] = -\dfrac{e}{mc} \mathbf{P} \times \mathbf{H}$ just as in the non-interacting case; or 2: if the above equation ($\dfrac{i}{\hbar} [H , \mathbf{P}] = -\dfrac{e}{mc} \mathbf{P} \times \mathbf{H}$) holds, then the energy spacing between levels different by one application of a ladder operator (and therefore the cyclotron frequency) is $\dfrac{\hbar e \mathcal{H}}{mc}$.
Dec
6
answered Why is surface tension parallel to the interface?
Dec
5
comment Are magnetic orbits possible?
Notice in the idealized limit where there are many small magnetics unformly spaced on the sphere or ball, there will be no magnetic field produced by either and thus no interaction force between the two.
Dec
3
answered Proof of Kohn's theorem