classical mechanics only applies for nonrelativistic speeds

that's science.

You go back to can we see something going faster than C. Well how do we measure that. With formulas assuming C is a constant. If not the formula is false. Circular reasoning.

We can't see something going faster than C as I said to you. Both lights are moving at C relative to us, just in opposite directions

If we use the relativistic formulas for kinetic energy of the electron and quadruple the voltage of the plates we get exactly the velocity we theoretically expect

which is something like .9c

Two lights approaching each other approach at double the speed of light. Proven by us seeing both stars at the same time. The theory does not work.

Steeve is right. Light can move at different speeds depending on the density of the medium

@Steve Angell that does not go against any of the postulates of relativity ..

they aren't approaching relative to us at double

they approach relative to Us at C

Which is what the theory expects

Then what about the speed your going? How does that get factored out

one approaches us at C, one approaches us at -C. Neither speed is exceeding C relative to us.

No but the speed of light approaching another light at 2C debuks it. You can not use the formula derived by the theory C is a constant to measure the speed in order to test the theory. That is circular reasoning and invalid.

@the21cat look up relativistic velocity addition formulas

Relative to us its -2C

?

Thats how vector quantities work

if you are in the middle of a junction and two cars are approaching you at velocity v in opposite directions what is the speed of each car realtive to you

they are both going at V, right?

V

All based on this theory that C is a proven constant. It is not and it is easily proven false with light.

that's what I am saying about two light beams

But not if you are in one car

yes and relativity describes that as well

it is nonintuitive

A car can not go the speed of light.

Yes i was using his example

No matter can according to the theory.

but the fact we can't accelerate an electron to C no matter how much voltage we put across a parallel plate should be suspect enough that C is special

Velocity v examplw

So question i guess

It's a textbook example of classical mechanics utterly failing at relativistic speeds

It just proves that method has a limit.

yes... Which is what I mean by domain of applicability I mentioned earlier

we still use classical mechanics for nonrelativistic claculations

When you ignore two beams of light approaching each other. You prove this is not at all about science.

If we drove a car toward that electron why wouldnt the velocity appear to go faster than light

Both of us basically have the same question here with different set ups i think

Because a scientist will say use our formula and then judge the speed based on it. It is like the square root of zero.