The distances (in feet) covered by a car t seconds after starting is given by the following function. s=- + 11t + 25t (0 t 6) Find a general expression for the car's acceleration (in ft/sec) at any time t (0 t 6). s"(t) = -61 + 12 X At what time t (in sec) does the car begin to decelerate? (Round your answer to one decimal place.) t = 2 X sec