Recent content by Mettra

The concept of what a derivative is will probably not come to you easily. There is a real importance and significance behind it which is very subtle (and did not reach me until I was out of high school altogether). I didn't understand it until doing numerous problems involving derivatives and...

With all due respect, if you want to have an inevitably meaningless semantic argument, you should choose an audience other than physicists. You asked several questions, and others have responded in order to try to be on the same wavelength with you, even providing examples and so on...

This is what the guy is trying to say: Forget this problem you have posed. Imagine now that you are an observer. You're not experiencing any acceleration (this is SR after all). Therefore, you can plop down a coordinate system and call yourself the origin. Since you are an observer...

Instead of thinking of it like that, think of it for the moment from this angle: When astronauts go up into space using a rocket, they feel a very large acceleration during the trip. Do we on Earth feel that acceleration (forget Newton's third law forces for now, some people on the ground...