Answer
$\mathrm{a}.\qquad 36$
$\mathrm{b}.\qquad 44$
$\mathrm{c}.\qquad 52$
$\mathrm{d}.\qquad 60$.
Work Step by Step
$\mathrm{a}.\qquad$Over $[0,2]$,
$v_{\mathrm{a}\mathrm{v}}= \displaystyle \frac{s(2)-s(0)}{2-0}=\frac{72-0}{2}=36$.
$\mathrm{b}.\qquad$Over $[0,1.5]$,
$v_{\mathrm{a}\mathrm{v}}= \displaystyle \frac{s(1.5)-s(0)}{1.5-0}=\frac{66-0}{1.5}=44$.
$\mathrm{c}.\qquad$Over $[0,1]$,
$v_{\mathrm{a}\mathrm{v}}= \displaystyle \frac{s(1)-s(0)}{1-0}=\frac{52-0}{1}=52$.
$\mathrm{d}.\qquad$Over $[0,0.5]$,
$v_{\mathrm{a}\mathrm{v}}= \displaystyle \frac{s(0.5)-s(0)}{0.5-0}=\frac{30-0}{0.5}=60$.
