 This is going to be an example on how to convert from kilometers per hour to meters per second using the dimensional analysis approach. If you didn't watch my first video on how to convert from one unit to the other using that approach yet, please watch it now. It should be down somewhere in the description. You will find the link. The question is, 72 kilometers an hour, how many meters per second is that? So I'm starting as I did in my last video by writing what I know. I know that we have 72 kilometers per hour. I'm going to introduce a fraction. What do I want to get rid of? I want to get rid of the kilometer. What I want to convert into is the meter. Now the question is how many meters are there in one kilometer and the answer is one kilometer is thousand meters. That one you have to look up, either you memorize it or you put it on a cheat sheet somewhere. And now if I do my dimensional analysis, I would have converted to meters per hour, but we want meters per second. So what do I want to get rid of next? I do want to get rid of the hour here, but the hour is at the bottom of the fraction, not at the top. So instead of writing the old unit at the bottom, here kilometers on top, so here at the bottom. So this time I'm going to write at the top hour. And what do we want to convert to seconds? Well, I have a bit of a blank out right now. I don't know what hour, how many seconds are there in hour, but I know how many minutes there are in hour. I know they are exactly 60 minutes in one hour. So doing my unit analysis, right now the unit I have is meters per minute. So no, I'm almost there. I want to get rid of the minute. Again, the minute was at the bottom, so half minutes. And one minute is how many seconds? Well, it's 60 seconds. Now if I look at this, the minute cancels the minute, and I will have meters per second as the unit. So all I have to do now is in my calcometer, I do 72 times 1000 divided by 1 times 1 divided by 60 times 1 divided by 60. And what I get is 20 meters per second. Section number that's almost worth memorizing, because we're lazy people in physics, so often you will get units like this 72 kilometers an hour, because it gives like a nice number in meters per second.