## Calculus: Early Transcendentals 8th Edition

$f(t)$ is not one-to-one.
The football's height changes from its lowest at $t=0$ to its maximum height and then back to its lowest height as it falls. Thus, there are two $t$-values for every $h$ except at the maximum height. Since $f(t)$ does take the same value twice, it is not one-to-one.