The net change theorem,
which is a restatement of the FTC II
from a different perspective, says that the net change in a
function is the definite integral of its derivative.

$$\int_a^b
f'(x)\, dx = f(b) - f(a)$$

Here, rather than a tool to evaluate an integral from $x=a$ to
$x=b$, we view $f(b)-f(a)$ as the (net) change in $f$ from $x=a$
to $x=b$.

In particular, the net distance traveled from time $t_1$ to time
$t_2$, which is $s(t_2)-s(t_1)$ where $s$ is the position
function, is the integral of velocity. Similarly, the net
change in velocity (final velocity minus initial velocity) is the
integral of acceleration. We go through some of these
computations in the following video.