Then in a nuclear plant we only make it decay faster by concentrating U235. I thought that the radioactive decays of the products (Ba(56,141), Kr(36,92) etc...) would also be speed up till the waste become less radioactive. At this point we could have diluted it back in the nature. Of course I knew there was something wrong here.

To answer @Lightness Races in Orbit, yes you could say there's a conservation of radioactivity. Correct me if I am wrong: If for each unstable isotope (N and Z) corresponds one type of decay, and the same for the products of the decay, then it follow a defined path and we have a law of conservation. If we can intervene on the type of decay of an isotope then there can be less natural decays resulting in unnatural radioactivity.If we follow the decays of Uranium 235 we can say that these decays have to happen sometime anyway.

what about decrease of temperature due to Venturi effect around the thermometer?

If you remove air, the circumference of the tire remains the same. That's why the tire looks flattened. Hence the distance driven for a full (2Pi) rotation of the tire remains the same

If you remove air, the circumference of the tire remains the same. That's why the tire looks flattened. Hence the distance driven for a full (2Pi) rotation of the tire remains the same.

the question is not a duplicate of "why glass is transparent". It asks if we could somehow model semi-transparency with a potential barrier: the two physical phenomenons are very different. I believe the analogies are only mathematical.

it doesn't work for me. Can you give examples with the objects used and distances?

..so the electron can feel its own field electric field when accelerated. One can do a simple model in one dimension. You start from a pure quantum state of the electron and the electric field. Then you accelerate the electron applying a translation operator...

Feynman answers the question in the case of an accelerated charged ball. The force is due to the delay action across the ball: the electrons inside the ball feel the electric field of other electrons with a tiny delay. The net electrostatic force is then non zero and opposed to the acceleration. So the force is electrostatic. In the case of one electron: we can shrink the ball till only one electron remains. The nature of the force shouldn't change. But how does it happen? You need a model with a spread wave function for the electron but you can still use a classical electric field..

I think it is a very good question!!!

if you have 1 gram of matter accelerated to 0.99c and 1 gram of stationary anti matter then in the center of mass frame you will have the same "relativistic mass" of both. That's symmetric and that's what you need for complete annihilation. Not 7 grams