I don't know if this applies, but I think I used to read that at least the Bay Bridge's cables were parabolas not due to the weight of the roadway but because that was structurally the strongest. But I have no details or source. —Dan
On Jul 2, 2015, at 3:02 PM, rwg <rwg@sdf.org> wrote:
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.