A car is traveling at a constant speed of 54 km/h when its driver sees a child run into the road. The driver applies her brakes until the child returns to the sidewalk and then accelerates to resume her original speed of 54 km/h; the acceleration record of the car is shown in the figure. Assuming x = 0 when t = 0, determine (a) the time t at which the velocity is again 54 km/h, (b) the position of the car at that time, (c) the average velocity of the car during the interval 1 s stt. (Round the final answers to one decimal place.) a(m/s) 2 1 2 0 4.5 tt(s) -6 The time at which the velocity is 54 km/h is The position of the car at that time is determined to be The average velocity of the car during the interval 1 stt is m. km/h.