To stop a car, first you require a certain reaction time to begin braking; then the car slows under the constant braking deceleration. Suppose that the total distance moved by your car during these two phases is 51.0 m when its initial speed is 78.5 km/h, and 24.2 m when its initial speed is 50.1 km/h. What are
(a) your reaction time and
(b) the magnitude of the deceleration?