Ig Nobel winner Audoly on the physics of the lasso

Basile Audoly — who shared the 2006 Ig Nobel prize for physics with Sebastien Neukirch for insights into why, when you bend dry spaghetti, it often breaks into more than two pieces — has a new study about the physics of rodeo lassoing. The new paper is:

An introduction to the mechanics of the lasso,” Pierre-Thomas Brun, Neil Ribe and Basile Audoly, Proceedings of the Royal Society A, vol. 470, no. 2171, November 8, 2014. They write:

“Trick roping evolved from humble origins as a cattle-catching tool into a sport that delights audiences all over the world with its complex patterns or ‘tricks’. Its fundamental tool is the lasso, formed by passing one end of a rope through a small loop (the honda) at the other end. Here, we study the mechanics of the simplest rope trick, the Flat Loop, in which the rope is driven by the steady circular motion of the roper’s hand in a horizontal plane…. In addition to Flat Loops, we find planar ‘coat-hanger’ solutions, and whirling modes in which the loop collapses onto itself. Next, we treat the more general case of a honda that can slide due to a finite coefficient of friction of the rope on itself. Using matched asymptotic expansions, we resolve the shape of the rope in the boundary layer near the honda where the rope’s bending stiffness cannot be neglected. We use this solution to derive a macroscopic criterion for the sliding of the honda in terms of the microscopic Coulomb static friction criterion. Our predictions agree well with rapid-camera observations of a professional trick roper and with laboratory experiments using a ‘robo-cowboy’.”

Here’s a video, prepared by other researchers long ago, about the basics of using a lasso:

EARLER INFO: Some physics of Trick Roping