An Olympic athlete runs and then jumps as far as they can. Categorize their motion from just after they leave the ground to just before they land in the sand pit.

A) Air resistance is not significant. The projectile motion equations are valid.

B) Air resistance is significant. The projectile motion equations are not valid.

Solution: A. A person is large in comparison to dust, has a density much greater than a balloon, is much slower than a bullet, and does not have a particularly broad cross-sectional area. The projectile motion equations are valid (will give reasonable predictions).