Sofia. Posted May 9, 2015 Report Share Posted May 9, 2015 Yeah, the derivation completely stopped me in my tracks for a while there! Should we create a new forum in the right category, since this should be under Exam Discussion? Who did the question on thermodynamics where you had to calc the new temperature of the gas? Did you guys get 500K? Yep, I got 500K. Silly of them to ask which process was adiabatic after that question! I mean, I think they even stated it in a later question which one was adiabatic... Thanks for that free point. Was there a question that asked which one was adiabatic? Lol I remember having to label the one which was isochoric I read isothermal... Since two were isochoric? Reply Link to post Share on other sites More sharing options...
nlebanon97 Posted May 9, 2015 Report Share Posted May 9, 2015 Who did the question on thermodynamics where you had to calc the new temperature of the gas? Did you guys get 500K? Yep, I got 500K. Silly of them to ask which process was adiabatic after that question! I mean, I think they even stated it in a later question which one was adiabatic... Thanks for that free point. Was there a question that asked which one was adiabatic? Lol I remember having to label the one which was isochoricThere were two possible choices right?? the one on the left and the one on the right. Because there was one that was increasing pressure and another decreasing pressure 1 Reply Link to post Share on other sites More sharing options...
ordinaryguy Posted May 9, 2015 Report Share Posted May 9, 2015 Yes nlebanon I think I ended up labeling the one to the right Reply Link to post Share on other sites More sharing options...
superspeed49 Posted May 9, 2015 Author Report Share Posted May 9, 2015 Who did the question on thermodynamics where you had to calc the new temperature of the gas? Did you guys get 500K? Yep, I got 500K. Silly of them to ask which process was adiabatic after that question! I mean, I think they even stated it in a later question which one was adiabatic... Thanks for that free point. Was there a question that asked which one was adiabatic? Lol I remember having to label the one which was isochoric Ya i labelled the isochoric one... Reply Link to post Share on other sites More sharing options...
nlebanon97 Posted May 9, 2015 Report Share Posted May 9, 2015 Yeah, the derivation completely stopped me in my tracks for a while there! Should we create a new forum in the right category, since this should be under Exam Discussion? Who did the question on thermodynamics where you had to calc the new temperature of the gas? Did you guys get 500K? Yep, I got 500K. Silly of them to ask which process was adiabatic after that question! I mean, I think they even stated it in a later question which one was adiabatic... Thanks for that free point. Was there a question that asked which one was adiabatic? Lol I remember having to label the one which was isochoric I read isothermal... Since two were isochoric?It was isochoric, and yes, there were two options, so I guess they were giving us a chance as we had a 50% chance of getting it right Reply Link to post Share on other sites More sharing options...
Sofia. Posted May 9, 2015 Report Share Posted May 9, 2015 Who did the question on thermodynamics where you had to calc the new temperature of the gas? Did you guys get 500K? Yep, I got 500K. Silly of them to ask which process was adiabatic after that question! I mean, I think they even stated it in a later question which one was adiabatic... Thanks for that free point. Was there a question that asked which one was adiabatic? Lol I remember having to label the one which was isochoricThere were two possible choices right?? the one on the left and the one on the right. Because there was one that was increasing pressure and another decreasing pressure But didn't they ask for isothermal? Or did I misread the question? Why would they ask for us to label one of them if two were isochoric?Damn it, then I misread yet another question haha! Reply Link to post Share on other sites More sharing options...
nlebanon97 Posted May 9, 2015 Report Share Posted May 9, 2015 Yes nlebanon I think I ended up labeling the one to the righti chose the left one, i think it was increasing, but ya i stayed a few minutes deciding which one was the correct one, i guess both Reply Link to post Share on other sites More sharing options...
ordinaryguy Posted May 9, 2015 Report Share Posted May 9, 2015 (edited) Who did the question on thermodynamics where you had to calc the new temperature of the gas? Did you guys get 500K? Yep, I got 500K. Silly of them to ask which process was adiabatic after that question! I mean, I think they even stated it in a later question which one was adiabatic... Thanks for that free point. Was there a question that asked which one was adiabatic? Lol I remember having to label the one which was isochoricThere were two possible choices right?? the one on the left and the one on the right. Because there was one that was increasing pressure and another decreasing pressure But didn't they ask for isothermal? Or did I misread the question? Why would they ask for us to label one of them if two were isochoric? Well there were questions in previous papers where you had to show the point where there was e.g. max displacement and there were a few points like that so I think you could choose one in this case too, and I am pretty sure it was not adiabatic/isothermal to be labelled because I saw the graph and before any questions were asked I checked which one is adiabatic thinking they would actually ask about it later but I didnt find such a question Edited May 9, 2015 by ordinaryguy 2 Reply Link to post Share on other sites More sharing options...
nlebanon97 Posted May 9, 2015 Report Share Posted May 9, 2015 Who did the question on thermodynamics where you had to calc the new temperature of the gas? Did you guys get 500K? Yep, I got 500K. Silly of them to ask which process was adiabatic after that question! I mean, I think they even stated it in a later question which one was adiabatic... Thanks for that free point. Was there a question that asked which one was adiabatic? Lol I remember having to label the one which was isochoricThere were two possible choices right?? the one on the left and the one on the right. Because there was one that was increasing pressure and another decreasing pressure But didn't they ask for isothermal? Or did I misread the question? Why would they ask for us to label one of them if two were isochoric?Damn it, then I misread yet another question haha! I'm nearly 99% sure it was isochoric, but don't worry, you probably gained marks everywhere else ahha Reply Link to post Share on other sites More sharing options...
Sofia. Posted May 9, 2015 Report Share Posted May 9, 2015 Well, that makes two questions I didn't read properly haha. Something to work on until chemistry, I guess! I got to get studying now, bye guys! Good luck with the rest of your exams! 1 Reply Link to post Share on other sites More sharing options...
ordinaryguy Posted May 9, 2015 Report Share Posted May 9, 2015 again to those who did thermodynamics, there was this last question saying that in adiabatic change work done was i think 210J, what was the change in internal energy.. so since that was adiabatic there was no heat exchange so the change in internal energy was -210J, did i get this one right? 1 Reply Link to post Share on other sites More sharing options...
whydidiprocrastinate Posted May 9, 2015 Report Share Posted May 9, 2015 again to those who did thermodynamics, there was this last question saying that in adiabatic change work done was i think 210J, what was the change in internal energy.. so since that was adiabatic there was no heat exchange so the change in internal energy was -210J, did i get this one right? Yep, just used the first law of thermodynamics for that one.Q = 0, Q=dU+W, W=210, -210=U Reply Link to post Share on other sites More sharing options...
ordinaryguy Posted May 9, 2015 Report Share Posted May 9, 2015 again to those who did thermodynamics, there was this last question saying that in adiabatic change work done was i think 210J, what was the change in internal energy.. so since that was adiabatic there was no heat exchange so the change in internal energy was -210J, did i get this one right? Yep, just used the first law of thermodynamics for that one.Q = 0, Q=dU+W, W=210, -210=U Thats great! Ok guys It's my first day here and I already cant leave But im back to studying, good luck everyone on paper 3 on monday Reply Link to post Share on other sites More sharing options...
Ossih Posted May 9, 2015 Report Share Posted May 9, 2015 (edited) again to those who did thermodynamics, there was this last question saying that in adiabatic change work done was i think 210J, what was the change in internal energy.. so since that was adiabatic there was no heat exchange so the change in internal energy was -210J, did i get this one right? Yep, just used the first law of thermodynamics for that one.Q = 0, Q=dU+W, W=210, -210=U Actually, U is not -210its cause 210 work was done ON the system so W is negative, so W is actually -210, which means ∆U is 210 J :$ Edited May 9, 2015 by Ossih 2 Reply Link to post Share on other sites More sharing options...
whydidiprocrastinate Posted May 9, 2015 Report Share Posted May 9, 2015 again to those who did thermodynamics, there was this last question saying that in adiabatic change work done was i think 210J, what was the change in internal energy.. so since that was adiabatic there was no heat exchange so the change in internal energy was -210J, did i get this one right? Yep, just used the first law of thermodynamics for that one.Q = 0, Q=dU+W, W=210, -210=U Actually, U is not -210its cause 210 work was done ON the system to W is negative, so W is actually -210, which means ∆U is 210 J :$ I don't know exactly what the question asked, but I'm glad I at least got the number right :X Nice PGs btw Reply Link to post Share on other sites More sharing options...
Ossih Posted May 9, 2015 Report Share Posted May 9, 2015 again to those who did thermodynamics, there was this last question saying that in adiabatic change work done was i think 210J, what was the change in internal energy.. so since that was adiabatic there was no heat exchange so the change in internal energy was -210J, did i get this one right? Yep, just used the first law of thermodynamics for that one.Q = 0, Q=dU+W, W=210, -210=U Actually, U is not -210its cause 210 work was done ON the system to W is negative, so W is actually -210, which means ∆U is 210 J :$ I don't know exactly what the question asked, but I'm glad I at least got the number right :X Nice PGs btw Thanks man Reply Link to post Share on other sites More sharing options...
Megamind Posted May 9, 2015 Report Share Posted May 9, 2015 In the data analysis question, I got my slope around 1 and the y intercept aro0und 0.97. Anyone else? Also, when you took out the x intercept by equation y=mx + c to zero, did anyone find the value of x weird? Because I got some -0.98 or something and by observing and extrapolating the graph mentally to the minus x axis, it didn't look more than a -0.10. Did anyone get L as 0.93?? In paper 1 (Tz2) there was a question about green light being emitted from two point sources which was just NOT resolved. So the question asked how to resolve it and there were two plausible options: use red light (higher wavelength so bigger theta) and use a circular aperture (again bigger theta since 1.22 is there instead of 1). What'd you guys write? I chose red light. Ossih, what did you write for the possible binary states? 15 or 16? I had no idea what the "s" in capacitance meant, so I had to skip that question . I mean I knew it was the Farad but I forgot the definition :/ and in all my years of Physics, I have never seen a freaking s as a fundamental unit . Randomnly ticked something and probably got it wrong. In Paper 2 (tz2), for question 6, everyone found the gravitational field strength as Del V/ Del T right? And therefore from the calculation the rocket cannot escape without further engine use. Sorry about the blast of questions in your face, I'm just too excited to know everybody's else's answers . Also, any other Paper 1 questions anyone found challenging? I keep forgetting :/ Reply Link to post Share on other sites More sharing options...
Sylvette Posted May 9, 2015 Report Share Posted May 9, 2015 Did anyone got the questions about T=2pi sqroot L/g? How did you solve for sqroot x? Did anyone choose question 4? If so, how did you find it? What did you write about the turbines being on water instead of land? Reply Link to post Share on other sites More sharing options...
Megamind Posted May 9, 2015 Report Share Posted May 9, 2015 I am TZ2 and I also found Paper 1 challenging, a few questions totally surprised me such as the artificial transmutation or unit for capacitance. Paper 2 was very easy compared to my expectations, I skipped the answers that were worth like 15 marks, the rest I could answer more or less. I had no idea how to solve the last question in section A about magnetic fields, the rest in section A were fine, I picked 6 and 7 in section B. I was planning on doing 7 and 8 but I just started the question number 6 and was like.. oh well. Hope it was a good choice. Not entirely sure I managed to solve the emf question completely, if that's the one you mean. What I did is I used emf = Blv. B was given and the length was the sum of three of the sides (since it had not entered fully, so the last one wasn't in the field as of yet). Since the thing was dropped, the velocity could be found from doing a bit of mechanics, with s = length of one end, u = 0 and a = gravity. Then you can use v^2 = u^2 + 2as to find the velocity. Sofia, Weren't we supposed to use the formula EMF = BAN cos theta, where B is the magnetic field, A is the area, and N = no of turns = 1 (as given) and cos theta = 1. Area = length squared and B is the magnetic field strength. That's what I used at least. Reply Link to post Share on other sites More sharing options...
Megamind Posted May 9, 2015 Report Share Posted May 9, 2015 Did anyone got the questions about T=2pi sqroot L/g? How did you solve for sqroot x? Did anyone choose question 4? If so, how did you find it? What did you write about the turbines being on water instead of land? The first part is pretty simple. I just took a point on the line of best fit, thereby getting the values of T and square root of X. And we were supposed to solve for root L, not x. So From the values of T and sq. root X I found a value for root L and squared it. Btw the turbines question is number 6. I wrote that they would get faster winds and increase power output, at the cost of increased maintenance costs from corrosion Reply Link to post Share on other sites More sharing options...
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