On Thu, Dec 12, 2024 at 4:33 PM Alan Grayson <[email protected]> wrote:
> > > On Thursday, December 12, 2024 at 2:13:26 PM UTC-7 Brent Meeker wrote: > > > > > On 12/12/2024 12:34 AM, Alan Grayson wrote: > > So if the observer in the car reported that the car crashed into the back > wall, > would you claim he was mistaken, or say had the wrong point of view? AG > > > He's certainly right. The question is where was the rear of the car *at > the same time* the front of the car hit the wall? > > Brent > > > The car length contracted is 7.2', and the garage length contracted is 6' > (both in car frame), so the rear of car hasn't entered garage when crash > occurs. AG > There is no contraction of the car length in the car's rest frame, at least not if you're talking about the period when it's moving inertially. "Rest length" means the same thing as "length in the car's inertial rest frame", both are equal to 12 in Brent's example. It's true of course that in this example the rear of the car hasn't entered the garage when the front hits the back wall of the garage, but that would not be true in the garage frame, that's the frame where the car's length is 7.2 and the garage has its rest length of 10. Jesse -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion visit https://groups.google.com/d/msgid/everything-list/CAPCWU3LHJr3g91HNj3FTj1%3D3uppzWPcQWKX8wmpZcLZtw0RPxw%40mail.gmail.com.
