Okay, So this problem is mainly about, uh, applying the ideas of, uh, heat engines, efficiency, whatever to something. And you might actually be particularly interested in in your day to day life, which is how much on a c, uh, will cost you. I'm sorry. That wasn't a c, right. Oh, refrigerator or conditioner. Okay. So basically, they first part, they want you to start out by converting, um, the traditional coefficient of performance too. This e r, let's see, was e r stand for gun energy efficiency ratio. And the big difference between K and E. R is e ers and units of BTU per watt hour, so you have to convert them. So that's part A So I e r equals K, which has units of, um, you know, Jules, her jewels. So it doesn't have any unit, but, um, it's I think it's easiest to write it this way. And you look in your book. You have the converted conversion. The goal is to get beat to you. For what? Our rate. So you go into your book to get the conversion of jewels. Bto, you got one? Um, one rule is Excuse me. One ptu is 10 55 jewels. Oh, my fives. And then sew together two watt hour. You want to consider how many jewels were burned for, um, for something burning at one watt. So that's one Jule per second for 3600 seconds. I'II an hour. So that's just gonna be Ah, 3600. Um, excuse me to be careful with this. I get such a simple calculation, but I actually struggled a little bit, Um, as I as I wrote this. So, yes. So then one what hour is actually 3600 jewels? Because that's how many jewels you burn if you're burning at one. What Montreal per second for 3600 seconds. Okay, so if you compute this, hopefully get what I got Actually got the wrong thing at first again because I kind of stumbled in that, um, logic on. So that's 3.1441 Excuse me? Pie stuck in my head sometimes. Case. So that's how you convert it. You just do K. Times 3.41 when that comes in handy in the next problem. So you need to calculate the e r. Um, for Was that an a C wasn't. Yeah, and a c um, that operates between 95 Edie. So it's K times three point for one and then K Ah, if you go to the formula in the book, chapter 20 Um, I think it's what the Andrews says. It's K Is this t c over th minus t c for a carnot engine. And that's what you're assuming that you're You're a C is, um, and then your tea cold is 80 plus 2 73 So I'll write that down T. C. Right. You need to convert to Calvin. Andi, Um, tea hot is 95 plus 2 73 Oops. Wow. What was I thinking? As I wrote that, maybe it's it's not trivial maybe to talk as I write. Okay, so 2 73 75 on dhe. If you compute, that's a stick. All these numbers in here, hopefully you'll get what I got for. Maybe you won't. I don't know. Um, which is 80. Yeah, I'm just going double track my calculations. Sometimes I get the impulse to do that. Um, yes, and it's tea cold, right? I'm just gonna double check the formula, too, while I'm at it. Yes, it is. Okay, great. My numbers ended up coming out pretty reasonable. Um, so I feel confident it. Um Okay, so, yeah, that's what I got. So now, for part C, it's asking for an a C. It's asking for how much it costs to run in a C for a whole year. That has in the e. R of 10.9. Okay, and then it's QC per year is, um, 10 1 was up 1.9 times 10 to the 10. So side note, um, I they completely ignored the fact that kay was written as qc overwork and both of murder out of my time. Um, probably a different way to think about it. If you do include that fact. Oh, my many of reasoning, but I didn't see any particular reason. Andrew, maybe I'm missing something. I don't know. Uh, anyway, so So our goal is to get how much energy is output so that we can figure out how much it cost so you can rearrange the um e. R is 3.141 times k k is qc over, um, work. And to obtain that work is Q c divided by E. R. And, um, keep in mind that if we're gonna use he are that has to be immune to be to you. And then this has to be in units of B T U per watt hour so that our work will come out in what hours we could easily convert. So we need to convert the heat to be to you. So we need to do that. Um, by dividing by 10 55 jewels per be to you. Um, so that was that's, like the heat that we should actually plug in. And then our years 10.9. So when I put that and I got 1.65 What, Like the stroke delay punishes me for going fast times turn to the six. What hour? Or maybe it's just that I decrease the pressure of the pen as I get past. That's probably it because I could do that. Yeah, I guess it pretty accurately. I don't know, Drew What I met. Okay, so 1.65 watt hours, and then, um now to get the price, we need to convert it to kilowatt hours, and then and then you acknowledge that you do a unit conversion to get the price. Given that it's 15.3 cents, it's for kilowatt hour. So then that's 1000 watts per one. Kill What? So now the what units will cancel, and I'll just show it. Although if you're already here, you're probably pretty good. It, um, unit conversion. But you never run out. Um m and Bugs. I'm just gonna convert it to, like, dollars. So it's, you know, 15 cents is, you know, $150.15. Um, her one kill what? And then the oh, the kilowatts cancel gay. And then we're just, like, left with dollars. So when I computer that I only brought these numbers down a bit, I got to 52 dollars, 1 79 cents. And then the next part asks you to calculate, um, what the price difference is if you have a different e. R in the e r. Waas. Um, what was that? 14 0.6. Okay, so basically, they're like, redo the calculation and PR is 14.6. How much do you save? So I'm not gonna write that out. I think we have a waist. I'll just kind of clearly, you know, highlight that when you're doing the calculation. Um, just switch this out for this is not 14.6. Um, and when I did that, I got, um, see, what did I got it? I got it. 180 eights dollars in 73 cents. Um, and so the difference between those two C $4.6. So this is a funny sign. It looks like it could be eliminate e or something is Ah, 60 64.3 domes.