Originally Posted by
Ted Crocker
If you are saying that a strip of fabric, with no weight added to the bottom is a pendulum, then fine.
The pendulum with a string of negligible mass and a high-density bob is called an ideal pendulum. A physical pendulum has mass along its lenth, so moments of inertia must be considered. I am proposing a uniform physical pendulum, which has the same linear density along its length. I am imagining the strip of cloth modeled as rigid, with a pivot at the top.
Consider the old physicist joke:
There is this farmer who is having problems with his chickens. All of the sudden, they are all getting very sick and he doesn't know what is wrong with them. After trying all conventional means, he calls a biologist, a chemist, and a physicist to see if they can figure out what is wrong. So the biologist looks at the chickens, examines them a bit, and says he has no clue what could be wrong with them. Then the chemist takes some tests and makes some measurements, but he can't come to any conclusions either. So the physicist tries. He stands there and looks at the chickens for a long time without touching them or anything. Then all of the sudden he starts scribbling away in a notebook. Finally, after several gruesome calculations, he exclaims, 'I've got it! But it only works for spherical chickens in a vacuum.'
Idea being, if you want to create a physics model of a real, complex system, start with a simplified approximation. Solve it, then add a complication. Solve and repeat.
Anyay, this probably has been done already. Watch Shrek or any computer-animated film with a woman in a flowing skirt. Animation companies pay physicists and mathematicians to create effects like this. Somebody at Industrial Light and Magic, Pixar or Dreamworks probably has a pleated skirt model at the ready.
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