We saw in the previous chapter that if a function s(t) gives the position of an object at time t, the derivative gives the velocity, that is, v(t) = s′(t). For each position function in Exercises , find 

(a) v(t) and 

(b) The velocity when t = 0, t = 5, and t = 10.

s(t) = -3t³ + 4t² - 10t + 5