The "Whip Like Physics of Fly Fishing".....from the archives of Discovery Magazine.
Propelling a line and attached lure such a great distance requires deft control of the body’s ability to impart momentum—the product of an object’s mass and velocity—to the rod and line. During a cast, the fly-fisher achieves peak energy in the flick-of-the-wrist stage, which “gives you all the momentum you’re going to get,” says Jeff Kommers, a technical staff member at MIT. While working on his Ph.D., Kommers entertained classmates with his restless efforts to parse the physics behind the process.