Cannon balls seek ellipses rather than parabolas. How does planetary roundness (point source gravity) distort catenaries? --rwg Supposedly, with the weight of the roadway, the Golden Gate Bridge cables changed from catenaries to parabolas. But what, really? The errors might be observable: The tops of the towers are inches further apart than the bottoms. On 2015-07-02 13:10, Hilarie Orman wrote:
A cool thing is that a square rotating on a catenary is is the inverse of a parabola rotating on a line.
The interesting questions are "why is a hanging chain the roulette of a parabola?" "why does a hanging chain have a succinct expression?" and "what does gravity have to do with it?"
Hilarie
Date: Wed, 1 Jul 2015 22:59:09 -0400 From: James Propp <jamespropp@gmail.com> Subject: Re: [math-fun] Draft of "The Lessons of a Square-Wheeled Trike"
I included the draft as an attachment in my earlier email, forgetting that "we" (math-fun) don't "do" attachments.
I've posted the draft at http://mathenchant.org/8-museum.rtf ; comments are welcome.
Jim Propp
On Tue, Jun 30, 2015 at 3:35 PM, James Propp <jamespropp@gmail.com> wrote:
I've finished a draft of installment #1 (as opposed to #0) of "Mathematical Enchantments", and I'd welcome comments.
Jim Propp
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