# 4 – A Different Model

Now, what if I gave you a more complex motion example? And I told you that our car starts at the same point at the zero meter mark, and it’s moving 50 meters per second forward, but it’s also slowing down at a rate of 20 meters per second squared. That means that every second the velocity decreases by 20 meters per second. This value is referred to as acceleration. Acceleration, in this case, equals negative 20 meters per second squared. This acceleration means that if the car starts at a speed of 50 meters per second, at the next second it will be going 50 minus 20 or 30 meters per second. And that the next second it will be going 30 minus 20, or 10 meters per second. The slowing down is also continuous, which means it happens gradually over time. For the next couple quizzes, I want you to keep in mind this question. Where will the car be after three seconds with this initial state? I also want to ask you, what variables do you need to answer this question? In other words, what values should be included in the state? And what motion model should we use to solve this problem?