Along a roadway, each milepost has an attached synchronized clock, synchronized with the clock at mile-zero. A 57 Chevy goes by at speed-v. Any one of the mileposts observes diminished clock face time on the dashboard clock passing by at speed-v. This is time dilation.

What does the driver say? “I am not moving at speed-v. I am at the origin of a co-ordinate system moving at speed-v.” But there is something he cannot say. “My co-ordinate system has diminished clock face time.” He cannot be the observer of this effect. Straight from EDoMB-1905-Section §4.

What happens when the driver does velocity addition? This is in Section §5. Now the 57 Chevy is going past the mileposts at speed-w. And the mileposts observe ENHANCED clock face time on the dashboard clock going by at speed-w.

What can the driver say? He cannot say his speed-w is the speed of a co-ordinate system, a co-ordinate system where the Chevy is “at rest.” In a sense, the Chevy is not on the milepost roadway. The Chevy is on a roadway which is moving at negative speed-v underfoot. Speed-w is indeed the speed of the Chevy with respect to the mileposts, but that is not the speed of Chevy with respect to the Chevy’s own blacktop. The new co-ordinate system of the Chevy is the negative moving blacktop, not the Chevy itself at origin-zero.

So what does the driver say about enhanced clock time? For the velocity-addition-formula to work, the driver must put this enhanced clock to work on the negatively moving blacktop. New time must be observed on the new axis. This flatly contradicts Section §4.

At great length: https://dibdeck.blogspot.com/

https://www.fourmilab.ch/etexts/einstein/specrel/www/

Le 11/09/2023 à 19:04, xip14 a écrit :
> Along a roadway, each milepost has an attached synchronized clock, synchronized
> with the clock at mile-zero. A 57 Chevy goes by at speed-v. Any one of the
> mileposts observes diminished clock face time on the dashboard clock passing by at
> speed-v. This is time dilation.
>
> What does the driver say? “I am not moving at speed-v. I am at the origin of
> a co-ordinate system moving at speed-v.” But there is something he cannot say.
> “My co-ordinate system has diminished clock face time.” He cannot be the
> observer of this effect. Straight from EDoMB-1905-Section §4.
>
> What happens when the driver does velocity addition? This is in Section §5.
> Now the 57 Chevy is going past the mileposts at speed-w. And the mileposts
> observe ENHANCED clock face time on the dashboard clock going by at speed-w.
>
> What can the driver say? He cannot say his speed-w is the speed of a
> co-ordinate system, a co-ordinate system where the Chevy is “at rest.” In a
> sense, the Chevy is not on the milepost roadway. The Chevy is on a roadway which
> is moving at negative speed-v underfoot. Speed-w is indeed the speed of the Chevy
> with respect to the mileposts, but that is not the speed of Chevy with respect to
> the Chevy’s own blacktop. The new co-ordinate system of the Chevy is the
> negative moving blacktop, not the Chevy itself at origin-zero.
>
> So what does the driver say about enhanced clock time? For the
> velocity-addition-formula to work, the driver must put this enhanced clock to work
> on the negatively moving blacktop. New time must be observed on the new axis.
> This flatly contradicts Section §4.
>
> At great length: https://dibdeck.blogspot.com/

The car is still at rest.

Even an accelerated frame of reference is at rest.

It is the external system which accelerates.

When I accelerate, it's the road that accelerates beneath me.

We must get rid of this idea of absolute reference.

Same thing for the speed of light, some say that it is constant when
changing the Galilean frame of reference. This is false by omission: it is
constant in all repositories, even accelerated ones.

We will say, but then the line becomes curved and longer.

It's true.

But on this curve the photons move at c.

R.H.

Einstein would know what I am talking about even though he never had a 57 Chevy.

The formula: V = ( v + w ) / ( 1 + vw/c² )

You add negative speed-v of the car’s personal roadway plus positive speed-w of the car on milepost ground, and then you scale that speed down the reduction factor, a denominator greater than 1.

The LT’s don’t do that. In a certain amount of time, the personal roadway moves a negative distance and the car moves a positive milepost distance. The LT’s add those distances, and then divide by time, divide by proper time scaled up* by the reduction factor. More time to go a certain distance, the slower you go.

* It is the opposite of time dilation, where proper time is scaled down.