Chapter 11 - Vectors and Vector-Valued Functions - 11.7 Motion in Space - 11.7 Exercises - Page 826: 7

a) $\textbf{v}(t) = <6t, 8t>$; Speed = $10t$ b) $\textbf{a}(t) = <6, 8>$

$\textbf{r}(t) = <3t^2 +1, 4t^2+3>$ $\textbf{v}(t) = \textbf{r}'(t) = <6t, 8t>$ Speed = $|\textbf{v}(t)| = \sqrt {(6t)^2+(8t)^2} = 10t$ $\textbf{a}(t) = \textbf{v}'(t) = <6, 8>$