A Rock Is Thrown Off a Cliff $s ( t ) = - 16 t ^ { 2 } + 16 t + 96$

Short Answer

A rock is thrown off a cliff. Its distance from the ground below at t seconds is $s ( t ) = - 16 t ^ { 2 } + 16 t + 96$ feet. What is the velocity of the rock when it slams into the ground?
Enter just an integer.