If a rock is thrown upward on the planet Mars with a velocity of $10 \mathrm{m} / \mathrm{s},$ its height in meters t seconds later is given by $\mathrm{y}=10 \mathrm{t}-1.86 \mathrm{t}^{2}$
(a) Find the average velocity over the given time intervals:
$$\begin{array}{ll}{\text { (i) }[1,2]} & {\text { (ii) }[1,1.5]} \\ {\text { (iv) }[1,1.01]} & {\text { (v) }[1,1.001] {\text { (iii) }[1,1.1] }}\end{array}$$
(b) Estimate the instantaneous velocity when $t=1$