1. a car accelerates from a stop at a rate of 2 m/s2 for 20s, then continues at a constant speed for 40s. Graph the speed vs. time of the car. What is the car's speed at 10s? What is the final speed?

2. A train traveling at 30m/s takes 60s to slow to a complete stop. Assume that the train's acceleration is constant as it moves down the track. Graph the speed vs. time of the train for 80s. What is the slope of the graph at 30s?