>> Hello class, Professor Anderson here. Let's try the motion diagram for a falling object. Let's say you stand on top of a building, and you drop a ball. And let's see if we can figure out what the motion diagram is going to look like for that ball. Well like we said before, the ball you can represent with a dot. So the first time that your camera takes a picture of this thing, the ball is at that height. The next time it is there, then it's there, then it's there, and then it's there. Is that object speeding up? >> (student speaking) Yes. >> Of course it is, right? We all know this. We've dropped things off tall buildings before. It starts at zero speed, and increases the speed as it falls. Is it accelerating? >> (student speaking) Yes. >> Absolutely. So let's see if we can plot y-- the vertical position of this thing as a function of time. All right. What do we need to know? Well, we probably need to know where is y equal to zero? So why don't we say that the ground is y equals zero, and let's say that we start up at h, okay? Y initial is equal to h. So on my graph here, I would start at h. That's where that first dot is. We know that the last dot has to be right there at y equals zero. And now, how do I connect them? Do I connect them like this? >> (student speaking) No. >> Do I connect them like this? >> (student speaking) Yes. >> (student speaking) No. >> No. Do I connect them like this? >> (student speaking) Yes. >> Is it just because I drew a solid line that you all said yes on that last one? This is the correct one, right? The y position as a function of time, initially doesn't change very much. They're very close together. As time goes on, those get further and further apart. Okay? So this is, in fact, the correct curve for y, the position of the object, as a function of time.