Arc Length Parameterization for Unit Circle: Cos(s) & Sin(s)

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Discussion Overview

The discussion revolves around the arc-length parameterization of the unit circle using the functions cos(s) and sin(s). Participants explore the implications of this parameterization on speed and acceleration, particularly in the context of constant speed and changing direction.

Discussion Character

  • Technical explanation, Conceptual clarification, Debate/contested

Main Points Raised

  • One participant notes that while (cos(s), sin(s)) provides a constant speed of 1 for the unit circle, the second derivative does not yield zero acceleration, which raises questions about the nature of acceleration in this context.
  • Another participant clarifies that although speed is constant, the direction of the velocity vector is continuously changing, leading to a non-zero acceleration due to the change in direction.
  • A later reply acknowledges the complexity of the situation, indicating a recognition of the nuanced nature of the discussion.
  • One participant poses a question regarding whether a vector function with unit length for all t implies that the vector is always perpendicular to its integrated vector, or if it can only be stated that its derivative will be perpendicular.

Areas of Agreement / Disagreement

Participants appear to agree on the concept that constant speed does not imply zero acceleration due to changing direction, but the discussion remains unresolved regarding the implications of unit length vectors and their relationships to their derivatives and integrated forms.

Contextual Notes

The discussion includes assumptions about the definitions of acceleration and velocity, and the implications of parameterization on these concepts remain open to interpretation.

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(cos(s), sin(s)) gives an arc-length parameterization of the unit circle so that the speed is constantly 1, but the second derivative doesn't give zero acceleration which should be the case with constant speed?
 
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THe speed is constant but you are constantly turning too right?

Acceleration is defined as the rate of change of velocity per unit time and since the velocity vector is changing direction then there's an acceleration that is not zero.
 
Ah, right.. tricky
Thanks
 
Does this mean that a vector which is a function of t and that vector has unit length for all t, will always be perpendicular to its integrated vector or can you only say that it's derivative will be perpendicular?
 

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