FIGURE EX1.18 shows the motion diagram of a drag racer. The camera took one frame every 2 s. (b) Make a position-versus-time graph for the drag racer. Because you have data only at certain instants, your graph should consist of dots that are not connected together.

Video transcript

Hello everyone. Let's go through this practice problem. An RC car is in motion and the photographer uses the burst mode photo feature to capture the moving subject. He took one frame per second. The given figure shows the motion diagram of the RC car draw. It's position versus time graph. We're not given any multiple choice options, but we are shown a diagram showing the motion of the car along the axis where we can see points along a green line that represent the car's position after each interval of time. Since there are no multiple choice options, the exact way you want to present your I your answer is gonna be a little open ended. But since it's just a graph, it's fortunately not going to be very hard. The first step of course is to set up the axes that we're going to use. We use a vertical axis to represent position and your horizontal axis to represent time. So this is the time axis, the vertical axis is position in meters. Now we must set up the scale. I'm gonna set zero for both axes at the origin and then for the time axis since none of the time values go any higher than 10 seconds, but go pretty close to it. I'm going to set the far end of the horizontal axis to seconds and then kind of base the interval between it around that. And I'll add the little ticks at, uh, an even number intervals. So 2468. So it's eight seconds, six seconds, four seconds and two seconds. True. Next, I'll represent the ticks on the vertical axis. The meters, the exposition never goes higher than 14 m. So I'll cap it at 14 and base the rest of the axis around that. And this part can always be tricky since you got to kind of estimate the position unless you're doing it on graph paper. But we'll say 2468, 10, 12. And that's about right now, we'll label these ticks 2468, 10, 12. All right. Now, we just have to go through all the points we're given in the problems diagram and label all those points on the graph. So the first thing we've shown is that for t equals zero seconds, we're at a position of 0 m. So this corresponds to the origin of the graph. The second point is when things are getting a little tougher where for one second, we're at a position of 2 m. So I'm gonna use a red dotted line to represent the position on both axes. So we're at a position of 2 m and we're looking for a point of one second. So on the horizontal axis, this is just halfway between zero and two seconds. So, right where these two dotted lines intersect is where we're labeling the point. And that's where the first where, so the second point will be for one second, 2 m and we'll continue this process for the rest of the graph. So for two seconds, we move up to the 0.4 m and that makes sense because we can see that it connects to both of the relevant axes for the problem. Continuing onward with this logic. So that's two seconds and 2 m continuing on with this logic for three seconds. In other words, halfway between two and four seconds, we reach 6 m. So that's the point right about here. And then for four seconds, we're at a position of 8 m. So for four seconds, we're right about here. And as we get further and further away from the axes, it can become more and more helpful to draw little labels to where we're at on the graph. After four seconds, there's a much bigger jump to our point at five seconds because at the five second interval, we jump up to 12 m. So 12 m and from five seconds halfway between four and six. So these come together at another line and then our next dot is at six seconds for m. So 13 m, that's halfway between 12 and four and right where we have six, so that dotted line will go right here. And finally, for our final point at seven seconds, we reach 14 m. So the final point on our vertical axis goes all the way to where we have seven seconds. We label that point right about here. And now we have completely filled out this graph. And really that is it for this problem. I hope this video helped you out. Please consider checking out some of our other videos, but she'll give you more experience with these types of problems. That's all for now. I hope you all have a lovely day. Bye bye.