The position of an object at time t is given by s (t) = - 9 - 3t. Find the instantaneous velocity at t = 8 by finding the derivative.

Given the function s (t) = - 9 - 3t, differentiating the function gives the instantaneous velocity. s’ (t) = - 3 This means that the velocity is not a function of time and is therefore constant. The velocity at t = 8 (or any time for that matter) is - 3 units/time.