I How to make something independent of the coordinate frame?

AI Thread Summary
The discussion centers on how to achieve independence from a coordinate frame in classical mechanics, specifically through the use of orthogonal unit vectors at a mass point's trajectory. It highlights that by defining a new set of base vectors, such as the trihedral formed by tangent, normal, and binormal vectors, one can express quantities that are invariant to the original coordinate system. An example provided is the horizontal throw of a mass point, illustrating how new base vectors can be established to make the position vector's components independent of the previous coordinate system. The trihedral consists of three base vectors that are fixed along the trajectory but vary in space. Overall, the conversation emphasizes the importance of redefining the coordinate system to analyze motion without dependence on the initial frame.
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what become independent of coordinate frame when using moving trihedral
In page 49, chap 8 of the book "classical mechanics point particles and relativity" of Greiner, there is the following sentence:
"In order to become independent of the coordinate frame, a set of orthogonal unit vectors is put at the point of the trajectory of the mass point given by ##s##."
Here, what become independent of the coordinate frame? And how using moving trihedral make some quantity independence of the coordinate frame?
A simple, concrete example to illustrate is welcome, like consider the orbit of mass point when throw it hozirontally
 
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I think it means that they choose new basevectors (##\vec{T}##,##\vec{N}##,##\vec{B}##) and new coordinatesystem to make components of positionvector indebendent of old coordinate system.
By putting by basevectors they mean defining new coordinate system.
Word trihedral indicates that there are 3 basevectors in new coordinatesystem.
Basevectors are not moving, but are not equal in every point of space. I do not know how these basevectors are defined outside trajectory, but the figure on page 50 and this illustration shows how these basevectors are on trajectory.
 
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