Chapter 11.5, Problem 76E

Velocity For each of the given position functions $s\left(t\right)$; find (a) the velocity function $v\left(t\right)=s^{\prime }\left(t\right)$ and (b) the velocity when $t=0,t=5$, and $t=10$. (See Example 5.)

Velocity If a rock is dropped from a 144-foot-high building, its position (in feet above the ground) is given by $s\left(t\right)=-16t^2+144$, where t is the time in seconds since it was dropped.

a. How fast is the ball moving 2 seconds after being thrown? 3 seconds after being thrown?

b. When will it hit the ground?

c. What is its velocity upon impact?