transportation

Necessary and possible dimensions

In everyday life 1D space and 1D time are typically used. We are concerned with how far away something is (travel length), how long will it take to get there (travel time), what the speed is (apart from direction). Unless we are doing something in which size or direction are important, 2D is all we […]

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Time conventions

The natural concept of time is solar time, which is based on the Sun’s position in the sky. But local solar time or local mean time varies by longitude. With the spread of railroads in the 19th century, there was a need for time zones to standardize time and simplify east and west travel. The

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Paceometer

We’ve all seen a vehicle speedometer, scaled in km/h or mph like this: A paceometer is made by adding another scale, as with the outer scale of minutes per 10 miles below (image source here): Fitness apps on smartphones can display distance traveled, travel time, and pace. In the article Pace yourself: Improving time-saving judgments

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Synchrony conventions

Reichenbach and Grünbaum noted that “the relation of simultaneity within each inertial reference frame contains an ineradicable element of convention which reveals itself in our ability to select (within certain limits) the value to be assigned to the one-way speed of light in that inertial frame.” (John A. Winnie, “Special Relativity without One-Way Velocity Assumptions:

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Lorentz and dual Lorentz transformations

I’ve written several related posts, such as one on the Complete Lorentz transformation. This post extends the previous post on the Galilean transformation to the Lorentz transformation, and what I’m now calling the dual Lorentz transformation, in order to show their similarities and differences. There are many expositions of a Lorentz transformation, such as here.

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Relativity at any speed

This is a summary of posts (such as here and here) about the application of relativity theory to transportation. This is different from applying theories of physics to other subjects such as economics since here it is real relativity, not some analogy. However, the application is an approximation, but that is the nature of transportation,

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