TSny's latest activity
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TSny reacted to Kostik's post in the thread Graduate Dirac's integral for the energy-momentum of the gravitational field with
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@anuttarasammyak Excellent! This was hugely helpful. I wish Dirac had been a little less cryptic. It's not often that one consults... -
TSny reacted to stovenn's post in the thread High School Applying the Gauss (1835) formula for force between 2 parallel DC currents with Like.
Aha! I see now how I slipped up by assuming that ##\mathbf{a} = 0## implies ##\ddot{r} = 0##. I had indeed subsequently gotten the...
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There is. If you practice Einstein's summation convention a little, where repeated indices imply summation:$$A_iB_i:=\sum_{i=x,y,z} A_i...
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TSny replied to the thread High School Applying the Gauss (1835) formula for force between 2 parallel DC currents.Equation (6) in the link reads $$\ddot r = \frac{\mathbf{r}\cdot \mathbf{\ddot{r}}}{r} - \frac{(\mathbf{r \cdot \dot{r}})^2}{r^3} +...
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TSny replied to the thread Undergrad Maxwell stress tensor.The last term on the right is wrong. This term should represent the divergence of just the part of ##E_{ij}## given by ##-\frac 1 2...
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