Development of a tumble number for use in accident reconstruction.

This paper discusses the development of the "Tumble Number". This is an empirically derived deceleration rate applicable in cases where a reasonably compact mass decelerates from a finite velocity while undergoing random and undefined rotation in multiple planes and making irregular ground contacts until it finally comes to a rest. The developed Tumble Number is strikingly close to 1 /2 g, a value which appears in certain theoretical formulas having nothing to do with tumbling objects.The significance of this similarit will be discussed at the end of the paper.