Question

A race car moves such that its position fits the
relationship:
x = (5.0 m/s)t + (0.75 m/s^3)t^3
where x is measured in meters and t in seconds. Determine the instantaneous velocity of the car at t = 4.0 s, using time intervals of 0.40 s, 0.20 s, and 0.10 s.