Initial Temperature - Physics - Solved Paper, Exams of Physics

Download Initial Temperature - Physics - Solved Paper and more Exams Physics in PDF only on Docsity! Roe w Physics 124 - Analytical Physics FINAL EXAM Tuesday, May 10, 2011,4- 7 PM SOLUTIONS => lee SIGN HERE NOW: Use a #2 pencil to make entries on the answer sheet. Enter ID informa- tion items 2-5, now, on the answer sheet before the exam starts... In the section labeled NAME (Last, First, M.I.) enter your last name, then fill in the empty circle for a blank, then enter your first name, another blank, and finally your middle initial. Under STUDENT # enter your 9-digit RUID Number. Enter 124 under COURSE; you may ignore the section number. Under CODE enter the exam code given above. During the exam, you may use pencils, a calculator, and three 8.5 x 11 inch sheets with formulas and notes. There are 30 multiple-choice questions on the exam. For each question, mark only one answer on the answer sheet. There is no deduction of points for an incorrect answer, so even if you cannot work out the answer to a question, you should make an educated guess. At the end of the exam, hand in the answer sheet and this SIGNED cover page. Retain the exam questions attached for future reference and study. When you are asked to open the exam, make sure that your copy contains all 30 questions. Raise your hand if this is not the case, and a proctor will help you. Also raise your hand during the exam if you have a question. Please have your student ID ready to show to the proctor during the exam. Possibly useful information: the gas constant R = 8.314 J/(mol-K), the Stefan-Boltzmann constant is o = 5.67x10-® W/(m?K%), in the ideal gas law R = 8.314 J/mol-K, 1 atm pressure ~ 1 x10° Pa, 0°C ~ 273 K = 82°F, at the earth’s surface g = 9.8 m/s’, the parallel axis theorem is I= LInpoutem + ml? and Ip = 1x107!? W/m? in the dB equation. ' Score Qie2,5 86% Jt e Sere A scientist in Antarctica observes “It is really cold today. The temperature is the same number in Fahrenheit and in Celsius.”’ What is the tempera- ture? Pick the closest answer. a a) 40°C Vet ler 32 q b) 20°C Fo 5 Tos gers? c} oc Te t= Ve 4 d) -20°C ~3g 3g te 47 HO The temperature of a fixed volume of an ideal gas increases by 50 K. The pressure doubles. What was the initial temperature? a) Volume is needed to determine the answer. 2y@T, “by 30K ao K cin Vy> NAT2 D 2 vy, =nehew d) -50K Ry e) 100K eae T, = Ts? 2% et (SO 2) 7,750K A metal ball has a hollow core. The volume of the core is half the volume of the ball. The ball is uniformly heated so that its volume increases 10%. How much does the volume of the core change? Choose the closest answer. 3 ie Croc ett -henoe. wm eore volume = frac mona | -5% c) 0% — does not change change om ball volu we d) 5% (valk does wot expand mls are.) @ 10%) , A 1.5 kg block of Aluminum with specific heat 910 J/{kg-K) and temper- ature 60°C is placed in water initially at 25°C. The water and aluminum come into thermal equilibrium at 30°C. Assuming no heat transfer except between the water and Aluminum block, how much water is there? The specific heat of water is 4190 J/(kg-K). Choose the closest answer. a) Okg Bua ~ QU water " 2 (Siwy) (Ato R308 ° (x) (Hao ge, SG) c) Like qa a = EB RG = ag Cannot be determined as specific heat is given in SR (kg-K), not J/(kg°C). 14. AV% 82%, 16. QA Fo 17. AN 18. \A % An insulated cylinder has one half filled with a gas at 300K, and the other half occupied by a vacuum. A foil separating the two halves breaks and the gas expands to fill the entire cylinder. Which of the following is true about the expansion process? a) onlyQ=0 b) only W =0 vo worltdoug — noth’ ing pos led c) only AU=0 => W=0 eLa=w= =AT=D ew £0 one of the other answers are correct. awd BATE Which of the following is true about an adiabatic process? ne beget eychong ¢ DOE a) Internal energy is constant. - . b) Volume is constant. QAO ®ran adialsadrc. process c) PV is constant. qd) Work done is 0. ey” Heat transfer is 0 How much work is done in an isothermal process with 1 mol of an ideal gas if Tinitien = 320 K, Proitint = 5.0°atm, and Vpinat = 0.235 m3? Voc WRT ihe > (Nga\ore Ze) a) W<10J => Te Conse TNT 2 BiB2 Kup sn? Moe b) l0I<W< 1005 Po ney” c) 1001 <W < 1000) v we ()( 839820) hee d) 10003 <W_< 10,0003 We Qwitty W = 2660 \n( 44,2) ey 10,000 < Ww v = 0080 5 We wer in My) What is y = C,/Cy for an ideal diatomic gas in which translation, rotation, and vibration are important? @ (Breed deavees af Sea efens 4/3 Cyr 3 R Co = CyrB 2 tr ad) 7/3 x. fe 4 An ideal monatomic gas has Vinitior = 0.25 m? and Pritt = 2.1x10° Pa, In an adiabatic process its volume doubles. What is the final gas pressure? Ca) 0.66x10° Pa PV = coustanr Ser edliababo proces “by 7X10 an 5 Sp ) 1.3105 Pa ye cp. 7 d) 3.3x105 Pa "ee 2) 0.93108 Pa fey monatomic es ws 19. GO Fe 20. 21, Fe), Casiest 0 @blem ay 2¥aw 22. 8"Io earrd Coe 9 tohp\ Rin Ory, exon A sample of gas cycles around a triangular path in the PV plane as shown. How much work is done by the gas for each cycle? we SP ON BONER QP femeerannnnnnen ernie a) 0 candle Care > b) 2Py% en P senna le Gai om ak oye "T y BF oVo WO Siva \ Stie VY eC ARE 0) 2PM og, ¥ oxen TV, 3Y, hygeoten vse Oe tyiondg =) we oa Pore + Roly What is the magnitude of the entropy change when 2 kg of water is con- verted from steam to water at a constant temperature of 100°C? It might help to know that the latent heat of vaporzation of water is 2,256,000 J/kg. a) 45,000 J/K dQ . C a b) -45,000 J/K ase Mel De2r6 cea) -\3.100 c) 12,100 J/K 7 373 ~ gay 12.100 JR @) 87000000 J/K An ideal Carnot engine operates between a hot reservoir at 650 K and a cold reservoir at 300 K. What is its efficiency? & 2 a) 0 \- ToL ye 328 = BSP Um b) 46% Tu 4S 6$O 0 e) Answer depends on whether the expansion is isochoric or isobaric. What is the entropy change of the entire system when 0.95 kg of water at 300 K is mixed with 0.95 kg of water of water at 360 K? Assume the water is an an insulated container and no heat is exchanged with the environment. a) 730 J/K Qs x | b) 350 /K wey AS= Ss ‘S “~ ny Wal be ro 380 J/K ) 3 I/K The 685 \5 unter heated res dsoo od/k ue ut corte * Aso Bur the Cmperdiuces Ore wet the SANG» So Xe wel dS pr the system & nero, DS euctem = (oei)(4'40) ( in( (330/300) + in (? 20 6) | +33 Tie ‘ 23. Several “wheels” roll without slipping on a surface. All have the same mass L Tw mand center of mass speed v. Which has the smallest angular momentum about its center of mass? with, Us ¥ a) A uniform solid disk of radius r. a wr Nis Ae a ate vt uD b) A cylindrical shell of radius r and small wall thickness t << r. al “ 4% c) A uniform solid disk of radius 2r. L Ge Ye 2) a see zwvt y phere OF Tadiis Fp ge ~ Spaere OL rad spiere of fadius ar. ~ gy 24. At aconstruction site, a 100 kg contractor walks Me the near ena im 1 oUF along a 10 kg, 3 m long board that is supported at both ends. What is the magnitude of the support force Fy, at the far end of the board? { 330 N | @) 380 N 2 pelo kg A 62), Qu 653 N F 4 | F oe d) 2940 N nest 3m e) 2990N i | ‘ * err od, muse guy to, Wn ntOeegh Bie | mx Hoey #7 Bae EB : mw W30 fs 2380 25. A 24 kg box floats 2/3 submerged in a liquid. what is the Gouyant force on the box, in Newtons? Choose the closest answer. Ga)_ 240 box 6 Claching 2 by 160 A\Ae c) 80 Frou d) 16 Sy 1. oun e) Need volume of box and / or density of liquid to determine the force. 2410 26. Consider the earth to be a uniform sphere of radius 6.4x10° m and mass 6.0x10"4 kg. What is the gravitational force of the earth on a 1-kg mass a distance r = 3.2x10° m from the center of the earth. a) 9.8N b) 3 x N oy 4 \ 32%, d) i N ~ inside the earth there is no gravitational force. e) 20.N LE te earth were a Poin Mase , wre word Wave &, - GWem . GMe y4m = BAN Buk = 6¢e ten pee hO2- ae aS . ; (reid we) 2h @uile* 1 ek a gehencal shell erewts “no Serce. OF sa a : pore ok! We ert mode tel2d arrratts Wwe & ‘a wuts, Stace Vopheuce pews, hE 2 aig yw Ve ok we. eaves § mass awk & > 2 lg VAAL mass ngide it , Fo only Abe,