In this problem we have on arrangement of a square. Um, where there's charges on two of the corners of the square, so the orientation is not unique. But for this point, I'm gonna choose it to where Q one is here. Cute too is here. Um And then they tell us that point A is in the middle, and point B is on the corner closest to cute, too. So that would, for my picture mean that b is up here. Now they tell us that each side of this square is three centimeters, so that means that 0.3 meters and then they give us some of these values. So Q one is equal to plus to micro Kula mes que tu is equal to minus two micro columns. Okay, so now what we need to do is we need to figure out some of these lengths here because we're gonna have to know these lengths in order to calculate Ah, the potentials. So first I'm going to do this triangle that I have drawn here. So this triangle is simply 0.3 0.3 and then a will be in the middle. So whatever we find the high pot needs to be the length from Kyu won A will just be half of that. So we have the high pot. News is equal to the square rope square root of two times 0.3 squared. And there's a two here because both sides of the same for this tells us that the high part news is zero 0.4 24 meters. Huh? And so now are our radius, Um, from one to a which will also be the same as the distance from que tu es. Since we have cemetery here is equal to half of this number, which is simply 0.21 meters. Okay, so now that we have this in part A, the book is asking us to find the voltage. Remember the voltage for a point charge. It's simply Q over four pi epsilon, not R. And then you must add up. The voltage is from every charge. So if we're trying to find the voltage at point A, we need to find the voltage at a duda que one plus a voltage at a dude. A cute too. So we can do that. The voltage et ai will be equal to Q one over four pi absolutely not are one plus que tu over four pi Absolutely not, aren't too. But since our one is equal to our two, this is simply equal to Q one plus que tu over four pi epsilon Not our one, or are too. And then we see that kyu won and que tu actually have the same magnitude but opposite signs. So when you add them together here, you're gonna get the voltage at point A is simply zero votes, okay, and that's it for part A. So now if we move on to part B, the book is asking us to find the voltage up at the top of our square at point B. So just to remind you this is point B, this is Q one. This is cute too. Okay. And we already found that this length here, okay, which is our one in this now is equal to 0.424 meters. So now we just do the same thing we did in part a. The voltage apart at location B is equal to Kyu won over four Pi epsilon not are one plus que tu over four pi absolute not are too. But now our wanted our two are different values are too is just a side of this square the distance between que tu and B So this is simply 0.3 meters And now you can simply plug in these values being very careful that Kyu won, um, and cute to our micro Coombs He must convert into cool ums and you'll find that the value is negative 1.75 times 10 to the fifth votes. Okay. And the reason this is negative is because que tu was actually a negative charge. You get a negative answer when you plug in it Now in part, See, we're gonna have a point a point Charge Q three equal to negative five times 10 to the negative six cool ums. And it's gonna travel from point A here, up toe point B. Okay. And we want to figure out how much total work is done as that point charges moving from A to B. So we can simply remember that work is equal to negative. Tell to you so this will be equal to negative. Ah, you final. Which is you be minus initial, which is Yuet huh? So this will simply be equal to you, eh? Minus you be. And now we just remember that you is equal to Q not V. Where cute not is the charge that we're considering moving or changing potential energy. So this will simply be equal to Q three, since that's what's moving times V A minus V b. Okay, so now we know he a is zero. So this whole thing goes to zero here, and what we're left with is simply the work from A to B is equal to minus Q two times the voltage at point B. Um, the voltage is negative. Thank you to is negative. So when we plug in these values, we find that the work from A to B is simply sorry. This is a Q three is simply minus 0.877 Jules, and this work is negative, which is, as we would expect, because a negative charge Charge three wants to move from low to high potential, and V B is at a higher potential. So it's trying to move to that point