3 ms·
If your starting point is a well understood theory that is known to conserve momentum (as a mathematical theorem), you design a complicated device using this th
by leni536 7y ago
If your starting point is a well understood theory that is known to conserve momentum (as a mathematical theorem), you design a complicated device using this theory and then within this specific design you find that momentum is not conservered then you should double check your calculations.
It first happened with classical electrodynamics (the EM drive) and now it happens with special relativity it seems.
To be fair, I am not arguing that conservation of momentum is 100% true. But starting from well established theories where conservation of momentum is a mathematical consequence seems to be a flawed approach.
- Enginerrrd 7y agoI can't believe this is so far down. This is exactly why I don't need to pay attention to someone's weird magnet arrangement or marble track geometry to create a proportioal motion machine, I know they're playing with conservative fields and it isn't going to work. However in this case, there is some significant acceleration which implies GR which is not in general conservative. I suspect it is though if you restrict yourself to the special case of accelerations with no significant gravity. In general, however, this is still the correct approach to thinking about such problems. If you can find a no-go theorem, then you needn't concern yourself with the complex details. That said, if you can find a weird place where it looks like momentum isn't being conserved, it probably is because you are inadvertently predicting an effect of the theory that will take care of that problem.
- humble_engineer 7y agoYou don't understand how the EM drive works, you just keep repeating a law, which is true, without any understanding how how the device actually works.