In Exercises use the position function s(t) = -4.9t + 200, which gives the height (in meters) of an object that has fallen for t

In Exercises use the position function s(t) = -4.9t² + 200, which gives the height (in meters) of an object that has fallen for t seconds from a height of 200 meters. The velocity at time t = a seconds is given by

Find the velocity of the object when t = 3.

lim s(a) - s(t) a-t