The motion of cats and stuff in free fall

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    Fall Free fall Motion
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Discussion Overview

The discussion centers around continuum mechanics, specifically the mapping between motions in configuration space and shape space, with a focus on modeling the motion of deformable bodies with constant angular momentum. Participants explore resources and literature related to these topics, including applications to free-fall scenarios.

Discussion Character

  • Exploratory
  • Technical explanation
  • Homework-related

Main Points Raised

  • One participant seeks resources for understanding continuum mechanics and the relationship between configuration space and shape space for modeling deformable bodies.
  • Another participant suggests a paper on non-linear solid mechanics as a starting point, referencing a book by Brannon that expands on the topic.
  • A third participant provides links to the frontmatter and introduction of a book, highlighting a chapter that discusses deformable media and bulk rigid motion, suggesting relevance to the original query.
  • A fourth participant shares notes from MIT that may contain useful information, although they express uncertainty about the applicability to the specific scenario of modeling animals in free fall.

Areas of Agreement / Disagreement

Participants do not appear to reach a consensus on a specific resource or approach, and multiple suggestions and resources are presented without agreement on their applicability to the original question.

Contextual Notes

Some resources mentioned may be behind paywalls, and there is uncertainty regarding the relevance of the suggested materials to the specific modeling of animals in free fall.

Who May Find This Useful

This discussion may be useful for those interested in continuum mechanics, modeling of deformable bodies, and applications of these concepts in physics, particularly in relation to motion and free fall.

etotheipi
Hey everyone, where can I learn fairly rigorousoly about continuum mechanics and specifically about how to map between motions in the configuration space ##\mathcal{C}## and motions in the shape space ##\mathcal{C} / SO(3)##? I would like to model the general motion of deformable bodies with constant angular momentum about the mass centre, thanks!
 
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From the publishers site

Frontmatter
https://iopscience.iop.org/chapter/978-0-7503-1454-1/bk978-0-7503-1454-1ch0.pdf

Introduction
https://iopscience.iop.org/chapter/978-0-7503-1454-1/bk978-0-7503-1454-1ch1.pdf

The rest are behind a paywall.

Check out the description of Chap 24
“Chapter 24 returns to the problem of deformable media, but considers the case that bulk rigid motion is the primary motion, with relatively small deformations with respect to an appropriately defined rigidly moving observer frame (e.g., turbine blade, human bodies in a braking automobile, etc). Phantom body forces are derived to allow solving the problem in a non-inertial material frame.”

24 Pseudo-body force for spinning problems 24-1
24.1 Kinematics of superimposed rotation (general analysis) 24-1
24.2 Fiducial body force for superimposed rigid motion 24-7
24.2.1 Special case: pure accelerated translation 24-8 (without rotation)
24.2.2 Special case: centrifuge (steady rotation 24-9 without translation)
24.2.3 Buried explosives 24-11
Reference 24-12

Sounds like your cat dropping experiment.
 
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I did also find some notes here, which at a glance look alright:
https://web.mit.edu/abeyaratne/Volumes/RCA_Vol_II.pdf

not sure if there's anything about spinny cats in them, though! I'm afraid, I'm probably going to have to put the whole modelling various animals in free-fall thing on hold for the moment, because I have write-ups due tomorrow 😔

1611520203178.png
 
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