In the 1968 Olympic games, University of Oregon jumper Dick Fosbury introduced a new technique of high jumping called the "Fosbury flop". It contributed to raising the world record by 30 cm and is currently used by nearly every world-class jumper. In this technique, the jumpuer goes over the bar face up, while arching her back as much as posible, as shown in figure P9.92a. This action places her center of mass outside her body, below her tack. As her body goes over the bar, her center of mass passes below the bar. Because a given energy input implies a certain elevation for her center of mass, the action of arching her back means that her body is higher than if her back were straight.
As a model, consider the jumper as a thin uniform rod of length L. When the rod is straight, its center of mass is at its center. Now bend the rod in a circular are so that it subtend an anhle of 90º at the center of the as shown in figure P29.92b. In this configuration, how far outisde the rod is the center of mass?
