The world record for a 100-m run is 9.8 s. Assuming that a pole- vaulter can only run 90 percent of the average velocity for the world-record 100-m run, calculate the maximum height that a pole-vaulter can jump regardless of the construction of the pole. Neglect the height that the pole-vaulter could attain from the strength of his legs and any added height that he could achieve by moving his hands up the pole. The world record for the pole vault is 5.5 m. Why is the world record greater than the apparent ability of the pole-vaulter on the basis of a simplified conservation-of-energy analysis?