$5.[6$ pts$]$ Scott throws his math textbook vertically from the edge of a cliff and watches as it goes up and then falls into the ocean below. The height of the book above the water $($in meters$)$ is a function of time and is given by $\backslash ($ h$($t$)=-4\mathrm{.}9$ t$^\{2\}+34$ t$+118\backslash ),$ where $\backslash ($ t $\backslash )$ is in seconds.

a$.$ Find the velocity of the book after $5$ seconds. Is the book rising or falling at this point? How do you know?

b$.$ Find the acceleration of the book at any time $\backslash ($ t $\backslash ).$

c$.$ Find the velocity of the book when it hits the surface of the water.