 In this demonstration we're going to see how to find the center of mass of an irregularly shaped object. For the object we're going to use the state of North Carolina. In order to help with this, I'll be using this piece of equipment. There's a nut tied to a string with a pin tied on the end. What I'll be doing is using this string with this pin and a weight attached to it, together with the map so that I can suspend the map from the pin and see where the string falls. So I'll begin by putting the pin here. This can be anywhere, but I'm just picking somewhere around Elizabeth City. I hold the end of the pin so that the map is suspended from my hand. So this means that the center of mass of the map will be somewhere along this vertical line. With a marker, I'll draw the line on there. It's kind of a rough line, but you get the idea. So we know the center of mass falls somewhere on that line, but we don't know where. In order to find out, we need to draw a second line to intersect with the first. So to do that, I'll put the pin in somewhere else, somewhere up here around Boone. Suspend it once more, draw another line. And that's enough to find the center of mass, which should be the intersection of those two. But just for good measure, we'll do it one more time to see if the third line also passes through that point. So I'll put this somewhere down around Wilmington. I don't have to draw the line for you to see that the string is passing very near that intersection point. So no matter where I put that pin, it should pass through that particular point. And let's see where that is. It turns out that it's very close to the city of Sanford. So if that really is the center of mass of North Carolina, then I should be able to balance the entire state on that particular point. Now, when I said that Sanford was the center of mass of the state of North Carolina, I was talking about this cutout of the state. Actually, the center of mass is influenced by the distribution of mass in the object. And for North Carolina, we know we have mountains to the west, and so that's going to increase the mass on the western end. And we have bodies of water distributed throughout the state in various places. So all of these will affect the actual center of mass of the state of North Carolina.