Question. Choose all the correct expressions for $\frac{?}{\text{b}\text{a}\text{r}}(v),$ the average velocity of an object moving along a straight line over the time interval $[a,b.($Reminder: $s$ is the position function, and a the acceleration$).$

$\frac{?}{\text{b}\text{a}\text{r}}(v)=\frac{1}{b-a}{\displaystyle \underset{a}{\overset{b}{}}}s(t)dt\frac{?}{b}$

$ar(v)=\frac{1}{b-a}{\displaystyle \underset{a}{\overset{b}{}}}v(t)dt\frac{?}{b}$

$ar(v)=\frac{1}{b-a}{\displaystyle \underset{a}{\overset{b}{}}}a(t)dt\frac{?}{b}$

$ar(v)=\frac{a(b)-a(a)}{b-a}\frac{?}{b}$

$ar(v)=\frac{v(b)-v(a)}{b-a}\frac{?}{b}$

$ar(v)=\frac{s(b)-s(a)}{b-a}$

We know from before that