isapiens

Thank you for the response, So n is going to be an unknown because i cant measure it. The only data i have is time vs pressure. I am still confused how i am going to use the data i have (time vs pressure change) to come up with a leakage value. I will work on it and see if i can come up with anything.

Well, help me out with PV=nRT part. I know that P(initial)V(initial)=nRT should be equal to P(finall)V(final)=nRT. Is that correct? I am not concerned with temperature because temp change in this case is negligible. So after i pressurize the system I will get my P(initial). I am confused about the volume (init) and volume (final). Is the volume in this case, the volume inside of the piping or the valume of air? If it is the piping, then V would be constant and something else would need to change. If V is the volume of air, then i dont know how that changes... Or does air spread evenly, meaning R would change? In regards to pressure vs vacuum, i am not really concerned because the piping is stainless steel and can withstand both. The system operates at slight vacuum anyway. The data i am measuring is the change in P after I pressurize the system and cap it off on both sides, basically testing whether there is any air leakage or in-leakage.

Hi Everyone. I am trying to perform a test on a system that will determine the integrity of the piping. It can be a pressure or a vacuum test. My idea was to 1) Cap off one side of the system 2) pressurize the line or draw vacuum from the open end 3) trend the change of pressure over time (say 20 minutes) Given that data i am a bit puzzled on how to calculate the "in-leakage" rate. I dont want that in-leakage to dilute my sample by more than say 10 percent. I dont think i can use PV=nRT because it is not a enclosed system - i am adding air to it or air is escaping. Please provide some guidence, Let me know if you have other ideas on how to get the same result performing a different test.

I dont really care if i get this problem wrong, its just a hw. But here is something else annoying i forgot to mention. Imagine that u shaped curve i was talking about - the average total cost curve. Well it doesn't just have one low point. It is flat at the bottom, so it has two points that are lowest and are equal to each other. But at the same time, only one of those points crosses the Marginal cost curve. (hard to explain and my scanner is broken, bummer) Its a bogus problem. As of now i will just put the point where those two graphs cross as the answer. I will let you know what is the correct answer after i get the homework back.

I have a problem were given the data i plot the marginal cost and average total cost curves on the same graph. Then the problem asks to: "Identify the lowest per-unit cost on the graph." I am confused about which curve am i supposed to use. Judging by the shape of the graph (u shaped)its gona be the average total cost one. However, i have a feeling the answer should be the point where those 2 graphs meet. But i cant understand what would that point actually mean. See if you can help me. PS: the book i am using is Essentials of Economics. Schiller 6e p126 problem 3