Answer
$\mathrm{a}.\qquad 15.3$
$\mathrm{b}.\qquad 20.2$
$\mathrm{c}.\qquad 25.1$
$\mathrm{d}.\qquad -4.9h+30$
Work Step by Step
$\mathrm{a}$.
Over $[0,3]$,
$v_{\mathrm{a}\mathrm{v}}=\displaystyle \frac{s(3)-s(0)}{3-0}=\frac{65.9-20}{3}=15.3$.
$\mathrm{b}$.
Over $[0,2]$,
$v_{\mathrm{a}\mathrm{v}}=\displaystyle \frac{s(2)-s(0)}{2-0}=\frac{60.4-20}{2}=20.2$.
$\mathrm{c}$. Over $[0,1]$,
$v_{\mathrm{a}\mathrm{v}}=\displaystyle \frac{s(1)-s(0)}{1-0}=\frac{45.1-20}{1}=25.1$.
$\mathrm{d}$.
Over $[0, h]$,
$v_{\mathrm{a}\mathrm{v}}=\displaystyle \frac{s(h)-s(0)}{h-0}$
$=\displaystyle \frac{(-4.9h^{2}+30h+20)-20}{h}$
$=\displaystyle \frac{h(-4.9h+30)}{h}\qquad$ ... h cancels ...
$=-4.9h+30$.
