 In this video, I want to talk about the electrostatic force, which sometimes is also called Coulomb's force. Now, what is the electrostatic force? It is the force of attraction or repulsion between two charged objects. If both objects are positively charged, they will be repelling each other, pushing each other away. If both of them are negatively charged, they will also repel each other. The only way that they will attract is if one of them is positive and the other is negatively charged. Now, if you want to calculate what the magnitude of Coulomb's force or the electrostatic force is, you can use Coulomb's law. There are two versions of this law. One is a vector equation, which I'm going to leave for another video. And there is the magnitude equation here, which says simply that the force is proportional to a constant called Coulomb's constant times the magnitude of the first charge times the magnitude of the second charge over the distant square. If we look at an example, let's say we have one charge of three times ten to minus six coulomb, and we have another charge of minus two times ten to minus six coulomb in the distance of one centimeter, and we want to know the force in between them. Now, we already know one is positive, one is negative, so we know that the forces will attract each other. Now, if I write this out, I had my force is equal to the constant, so times nine times ten to the nine Newton square meter per coulomb squared times my first charge, which was three times ten to the six minus six coulomb times minus two, but it's a magnitude equation, we just take the magnitude of the charges, so two times ten to the minus six coulomb and then over the centimeter we need to convert to meters, otherwise with this constant we wouldn't get Newton's, so divided by one times ten to minus two squared square meter. And if you look at the units, the square meter cancels out, the coulomb cancels out, and they end up with Newton as I should for my force. Now, if I type this in my calculator, I know I'm going to mess up the powers of ten, so I like to do this separate, so for my calculator, I'm going to just take the numbers nine times three times two over one squared, actually I don't need a calculator, that's 54, right? And then for the powers of ten, I'm going one by one, so I have plus nine, minus six, minus six, and then minus minus four, two times minus two, so plus four, so it gives me ten to the power of nine minus six is three minus six is minus three plus four is plus one, so that gives me five hundred and four key newtons.