## Calculus (3rd Edition)

(a) The rate of change of $L(t)$ is $v(t)$, and $v(2)=2^2=4$. (b) $L(t)$ is defined to be the total distance traveled, which is only equal to displacement when the path is a line. The problem states that the path is a parabola, so the distance traveled is greater than the displacement from the origin.