The driver in a moving car applies the brakes. The car slows to a final speed of 3.15 m/s over a distance of 40.0 m and a time interval of 9.45 s. The acceleration while braking is approximately constant. (a) What is the car's original speed (in m/s) before braking? (b) What is its acceleration (in m/s2) during this time? (The car's initial velocity is in the positive direction. Indicate the direction with the sign of your answer.)