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1d
reviewed Reject Does shaking a kettle whilst boiling increase the temperature faster than a statically-placed jug?
1d
reviewed Reject 2 airplanes same size and shap different mass
1d
reviewed Reject Conductive n-type material in pn junction
1d
reviewed Reject Can the linear momentum of a system be constant, even though its centre accelerates?
1d
comment Equation describing magnetic hysteresis
@cjorssen, "Snakes. Why'd it have to be snakes?"
1d
reviewed Reject Misunderstanding about Reynolds number
1d
comment Why treat complex scalar field and its complex conjugate as two different fields?
Please consider adding the Coleman reference to your answer. Adding his specific example (naive vs. sharp approaches) would be even better.
1d
reviewed Approve Why torsion vanishes in supergravity?
Feb
2
reviewed Reject Dark energy vs. gravity
Feb
2
reviewed Reject Latitude from initial conditions
Feb
1
reviewed Reject Why is Iron the most stable element?
Feb
1
reviewed Approve What influence has the distance of the moon on the height of the tides?
Jan
29
comment Biot-Savart law for linear current from Ampère's with multivariate calculus
@Self-teachingDavide, re your calculation, maybe I am missing the point, but your result does not surprise me. Since, by your assumption, $\boldsymbol{J(x)}=0$ at the point of interest $\boldsymbol{x}$, one expects to find $\boldsymbol{\nabla^2 A(x)}=-\mu_0 \boldsymbol{J(x)}=0$ there.
Jan
29
comment Biot-Savart law for linear current from Ampère's with multivariate calculus
@Self-teachingDavide, I don't have a direct solution method of (5). The point of this answer was to show that (9) is a solution of (8) from Coulomb's law (math from physics). Since each of the 3 vector components of (5) is the same as (8), each of the 3 vector components of (10), which are the same as (9), must be a solution of the corresponding component of (5).
Jan
29
reviewed Approve From your 2 point charges, does the electric field fall off like $\frac{1}{r}$ or $\frac{1}{r^2}$?
Jan
29
reviewed Approve Can the Earth leave orbit if the population of humans and other live forms increases?
Jan
28
comment Biot-Savart law for linear current from Ampère's with multivariate calculus
@Self-teachingDavide, sorry, I am very fond of Helmholtz's Theorem but should have checked its derivation before including it. In fact, I believe it is not necessary to the development here (and is typically not referenced in the intro courses' approach that I am recapitulating). I have edited my answer to remove it.
Jan
28
revised Biot-Savart law for linear current from Ampère's with multivariate calculus
removed references to Helmholtz's theorem
Jan
28
answered Biot-Savart law for linear current from Ampère's with multivariate calculus
Jan
27
reviewed Reject How does faster than light travel violate causality?