Mark left his house to drive to work. As, he drives down his street, his speed increases steadily until he sees the stop sigh at the end of the street. Then his speed decreases steadily until he comes to a complete stop at the stop sign. After waiting at the stop sign for his turn to go, Marc's speed increases steadily until he reaches the speed limit. Mark then drives at a constant speed until he approaches his office. He slows down steadily and comes to a complete stop in front of his office.