PHYSICS: Cracking the Whip

Shape of a cracking whip.

The crack of a whip is produced by a shock wave created by the supersonic motion of the tip of the whip in the air. A simple dynamical model for the propagation and acceleration of waves in the motion of whips is presented. The respective contributions of tension, tapering, and boundary conditions in the acceleration of an initial impulse are studied theoretically and numerically.

Cracking the Whip to Make Gasoline

Reading, writing, and the whip.

On the physics of moisture-induced cracking in metal-glass „copper-silica... interfaces

Environmentally dependent subcritical crack growth, or stress-corrosion cracking, along ceramic-metal interfaces is studied for the silica glass-copper system. Tests were conducted in various gaseous and liquid environments in order to determine their relative effects on stress-corrosion cracking and to gain some insight into the mechanisms that control interfacial crack growth. In agreement wi...

On Animating Whip-type Motions

This paper presents algorithmic methods to generate progressive, whip-type motions, characteristic of experienced humans in high speed athletic activities like throwing and striking. In deriving these methods, we deduce boundary conditions for dynamic quantities by analyzing the motion of a two-link system. A control algorithm based on cascading gains is introduced and is shown to be e cient wh...