Miscellaneous Papers

Elastic instability model of rapid beak closure in hummingbirds
Smith ML, Yanega GM, Ruina A.
J Theor Biol. 2011 May 18. [pdf]

The "Push-Me Pull-You" Boat is Better Still (PDF)

Ruina, A., 1978 (in revision for American Journal of Physics).
My first paper, on sailing upwind and sailing downwind faster than the wind, is in its nth year of revision (subtract 1978 from current date to calculate n).
For related you-tube videos, search for DDWFTTW, DWFTTW, Direct down wind faster than the wind, or down wind faster than the wind.

Random Mechanics

Unpublished semi-ideas from my friend Jim Papadopoulos and myself.
Email Jim, Andy

Rolling and Sliding of spinning things

Euler's Disk, Jellett's egg, and Moffatt's Nature,
Comments about things that go in circles on the ground.

Muscle motor

Annoying things at Cornell

A partial list of gripes.

Talk on brief introduction to mechanics (PDF)

Rant about "internal" and "external" work in biomechanics (PDF)

Review of Mark Levi's book, Why Cat's Land on Their Feet and And 76 Other Physical Paradoxes and Puzzles for the American Journal of Physics, August 2012 (PDF).

Krugman's who's-zooming-who traffic paradox, July 2013 (PDF).

Bump-Stock Gun Dynamics, Febuary 2018 (PDF).

An essay about how to write a report.