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5

As John Rennie wrote in his answer, what one should consider is not a generic $\Delta t$ but the period $\tau$ which is a positive number. However positivity also arises form coherence with other relations. In particular, in relativistic quantum mechanics $E= \sqrt{\hbar^2 \vec{k}^2 + m^2c^4}$. For $m=0$ you have $E= \hbar |\vec{k}| = \hbar \omega = h\nu$ ...

4

Energy, frequency and period are all scalars. It's correct to write: $$E = \frac{h}{\tau}$$ where $\tau$ is the period, but the sign of $\tau$ does not change if you run time backwards so the sign of energy doesn't change in QM either.

1

1) one way to find out is to measure motion of charged particles in their own fields on the microscale and infer which EM fields give best agreement with the observed motion. This was never done, because there are always EM fields of other sources and the motion is hard to measure accurately enough. 2) it depends on what you mean by "force is time-reversal ...

-1

Energy would exhibit both positive as well as negative energy if it were a living entity. So first one must answer is time alive? To solve any equasion shouldn't you know the values of all propertys within it?Idetify the propertys first. Only then could you solve it.

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