Exercises refer to Examples 9 and 10 in this section.

An object is dropped from a small plane flying at 6400 ft. Assume that a(t) = -32 ft per second and v(0) = 0. Find s(t). How long will it take the object to hit the ground?

Examples 9 

Suppose the velocity of an object at time t is v(t) = 6t² - 8t and that the object is at 5 when time is 0. Find s(t), the function that gives the position of the object at time t.