space & time

Matters relating to length and duration in physics and transportation

Modes and measures

What is the “distance” between two point events? That would include the length in both space and time. The measurement of the length of time between events depends on the mode of travel between them. For example, the time between leaving one’s residence and arriving at work depends on how one commutes. If the trip […]

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Problems in mechanics, part 2

How practical is the mechanics of time-space? It’s at least as practical as the mechanics of space-time and in some case is easier to understand or more appropriate. This post continues a series to illustrate this based on the website Physics: Problems and Solutions, Kinematics. Problem 2.1 Is it possible that a vehicle could relentate†

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Measurement by motion

Traditional expressions and units are often associated with motions. For example, English farmers used the distance and area of land that their animals could plow for units of measure: A furlong was the length of a plowed furrow, i.e. furrow-long. An acre was the area that could normally be plowed by an ox in a

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6D as two times 4D

Although the six dimensional space-time invariant interval represents space and time, we do not observe it as 6D. Instead, we observe space and time as 4D in one of two ways. The full 6D space-time interval expressed in spatial units is: s² = Δr² – c²Δw² = Δr1² + Δr2² + Δr3² – c²Δw1² –

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Transformations for one or two directions

A bidirectional transformation applies to all observers, and so must work for any direction, including observer and observed with the roles switched. A physics for all observers should be bidirectional if possible. This works for mechanics but for thermodynamics entropy is inherently directional. The Galilean transformation is for one direction with no characteristic (modal) rate.

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Travel time and temporal displacement

There’s a basic distinction between the travel distance (or flight length) and the displacement. There should be a corresponding distinction between the travel time (or flight time) and the temporal displacement – which I’ll call the dischronment (dis-time-ment vs. dis-place-ment). The travel time is the total duration of the trip, and the travel distance is

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Galileo doesn’t lead to Lorentz

I haven’t mentioned this before because I have a solution to it but there is a problem with deriving the Lorentz transformation from the Galilean transformation. If one uses the spatial Galilean transformation, the gamma factor leads to the Lorentz transformation. But if one uses the temporal Galilean transformation, the gamma factor does not lead

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Transformations for time and space

The standard transformation of reference frames begins with two frames in uniform relative motion along one axis (usually called x). Here we take the spatial axis to be the r-axis, which parallels the spatial axis of motion. Similarly, the temporal axis is taken to be the t-axis, which parallels the temporal axis of motion. One

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Six dimensions of space-time

If one travels a distance X east, then goes a distance Y north, that is the same as going a distance √(X² + Y²) northeast. But if one travels for a time X east, then goes for a time Y north, is that the same as going for a time √(X² + Y²) northeast? No,

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