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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 Rigorously prove that electric field is zero in a perfect conductor
Nov
18
comment Non equlibrium thermodynamics: How exactly does Euler Homogenous Function Theorem allows one to go from total differentials df to f itself?
At least I think so, otherwise it would be a math question.
Nov
18
comment Non equlibrium thermodynamics: How exactly does Euler Homogenous Function Theorem allows one to go from total differentials df to f itself?
There is no derivation. That is what's confusing. There's a derivation of The Euler Theorem, but not of why the Euler theorem implies the result given on the left.
Nov
17
answered How, in practice, could instantaneous signalling violate causality?
Nov
17
reviewed Leave Open Work Done Against Magnetic Force
Nov
17
reviewed Leave Open Rolling without slipping
Nov
17
comment Rolling without slipping
You say the friction force is $\mu m g \cos \theta$. Does this make sense for $\theta =0$?
Nov
13
reviewed Leave Open Terminal speed of a body in a gravitational free fall?
Nov
13
reviewed Approve suggested edit on What is a gauge in a gauge theory?
Nov
13
comment Biot-Savart and Amperes law inconsistentcy
Could you explain the second method? I don't understand it. What curve are you integrating around and how did you do the integral?
Nov
10
answered Can you see back in time?
Nov
7
answered Difference between kets $\left| -x\right\rangle$ and $-\left |x\right\rangle$?
Nov
5
answered Definition of torque for a continuous body
Nov
5
answered How exactly does applying the Equipartition Theorem to radiation leads to UV catastrophe?
Nov
4
comment Is this expression for the kinetic energy of a spinning disk revolving about a second axis correct?
But you are right that, for example, we can't say the kinetic energy of the disc is $\dfrac{1}{2} I \omega_1^2$, where $I$ is the moment of inertia of the disc about the blue point.
Nov
4
comment Is this expression for the kinetic energy of a spinning disk revolving about a second axis correct?
Oh I thought you were talking about the green dot here, not the blue dot. For the blue dot, you are right that the motion of the disc is not a rotation about the blue dot at some angular velocity. The way that $\omega_1$ is defined is just the rotational speed of the green point around the blue point or equivalently, the rotational speed of the center of mass of the disk around the blue point.
Nov
3
comment Is this expression for the kinetic energy of a spinning disk revolving about a second axis correct?
Now there is an additional quesiton of should the frame of the axle also rotate with the axle or should the coordinate axes be always aligned with the lab frame. The difference between these two choices is what makes up my answer to the OP's question.
Nov
3
comment Is this expression for the kinetic energy of a spinning disk revolving about a second axis correct?
Just view the motion in the frame whose origin is moving with the axle. Then there will be a well-defined $v_1/r$.
Nov
3
comment Is this expression for the kinetic energy of a spinning disk revolving about a second axis correct?
@Simha I am not sure I understand your question. Is your quesiton "How can a disk rotating about a moving axle have a well difined angular velocity?"
Nov
2
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