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Unformatted text preview: MEEN 227 Â« Fall 2006, Exam 1 Name 3 a (Â«Jâ€”3â€™40 n5. ID No. 1. Multiple choice problems worth 2 pts each. Circle the answer that is the most appropriate or
CIOSest (numerically) to your answer. 1. Routinely writing down as a ï¬nal answer the maximum number of digits that can be displayed by
your calculator is A. Correct C. Required . Misleading D. Helpful A. energy C. heat B. work 0 mass 3. A mass of 3 1bm is accelerated at a rate 5 ft/s2 by a force. What will be the acceleration rate in ï¬/s2
if the mass and force are both doubled. 5 C. 20
B. 10 D. Cannot be determined F} :7 M'Ql 1:2sz 4.2 Farapl
QFâ€˜ =Qm'ql "â€˜3'ng Fl E"â€œ = 4 7:: = â€œM Mr 1 a :61; tsg'Ã©sa 4. The law that serves as the fundamental basis for thermometry and temperature measurement in
general is A, Rankineâ€™s Law Â© Zeroth law of thermodynamics B. Boyleâ€™s Law D. First law of thermodynamics MEEN 227 â€” Fall 2006, Exam 1 Name 8 O L.) V7 5 IDNo. 5. An isothermal process is:
A. A process Where pressure remains constant B. A process where volume remains constant (9 A special polytropic process where n = 1. D. A special polytropic process where n = 0. 6. Which of the following have only intensive properties? A. T,P,H C. m,v,V x,h,u D. v,T,U 7. The critical point deï¬nes A. The point when solid water becomes a vapor.
B. The temperature when any substance becomes a vapor
C. The temperature and pressure when water is no longer liquid The temperature, pressure and volume at which an equilibrium phase change between
vapor and liquid ceases to exist. 8. Total work is
A pathâ€”dependent function of a process C. An exact differential B. An extensive property of a substance D. A quantity used to deï¬ne a state I K
MEEN 227 â€” Fall 2006, Exam 1 Name SOLUngnJ ID No. 9. To what thermodynamic variables do the letters on the ï¬gure correspond? A. y=P,x=T,i=v1,j=V2,v1>\/2
13 y=TaX=VaiZPLj=P2aPI>P2 C. y:P,X:V,i=T1,j=T2,T1<T2 y=Pax=V9i=T1,j:T2,T1>T2 10. Determine the compressibility factor for Râ€”134a at 80.3 atm and 280 Â°F. A. 0.6 C. 0.2 P.â€” goedm 2c weâ€˜regï¬;
: â€œâ€˜30 [9310;
Â® 0.4 D. Less than 0.2 .
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4 MEEN 227 â€” Fan 2006, Exam 1 Name 39 ID No. II. Four workâ€”out problems worth 20 points each. 1. The gravitational acceleration g as a function of altitude h above sea level is approximately given
by g : a â€” bh, Where a = 9.81 III/3602 and b m 3.32 X 10â€”6 secâ€”2. Determine the altitude above sea
level where the weight of an object decreases by 3 %. (20 pts) F: mgr PPM :@.<3lmn
gnawâ€”bin) 0.0131931): â€˜1â€˜31â€” 3.352 x/oâ€˜Ã©k 0910191) _ at?! (A
 332 x/Oâ€˜Ã©â€™ 333$ y/o3m r MEEN 227 â€”â€” Fall 2006, Exam 1 Name 3 l :l: a n S ID No. 2. Consider that the atmosphere is a column of air 65,000 ft tall (measured from sea level) rising
above you. Compute the average speciï¬c volume in ft3 /1bm. If you make any assumptions in order to
work this problem be sure and state them clearly. (20 pts) AXSUMc (PO: Â¢ 3: Â£Â£Sa
â€˜P: W. (0% [ma 6 la: $33900 lie. : ?,OQ?Qw0â€”Ã© â€œ72'?â€ '39. PM] (Am43Â¢
Ln â€”{3{" pt: Iâ€, _32 MEEN 227 â€” Fall 2006, Exam 1 Name 3 o A; 11:4 :0 5 ID No. 3. Air in a vertical ï¬ictionless pistonâ€”cylinder device (piston is on top as shown in the ï¬gure) is
initially at 14.6 psia and T = 75 0F. The initial volume in the device is 3.53 13:3. The cylinder is
connected to a highpressure air source via a line with a closed valve. The valve slowly is opened
and 0.5 lbm of air is admitted to the cylinder slowly. The ï¬nal temperature in the cylinder is 260 Â°F. A. Determine the speciï¬c volume in ï¬3/lbm in the pistonâ€”cylinder
device before the valve is opened. (5 pts) B. What is the ï¬nal pressure in psia in the pistonâ€”cylinder device?
State 1 Note: if you cannot ï¬nd this pressure and need it later, use 20 psia
P1 = 14.6 psia (not the correct value). (3 pts)
T1 = 75 Â°F
v1 = 3.53 ft3 C. What is the ï¬nal mass in the piston cylinder device? (5 pts) valve ls mmally D. Determine the total work in Btu done during the process. (7 pts) closed.
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â€˜9 U: 31â€˜, Rm} : 0. Evocl 3% 7,: 45Â°F 1Â» Â«157.6?
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M : Ig ï¬‚ â€œ3 r a ' qâ€” ? â€˜ (if ____ï¬___________.___,.______,/ MEEN 227 â€” Fall 2006, Exam 1 Name So 4 a ï¬g ID No. 4. A cylinder ï¬tted with a frictionless piston contains Rl34a at 20 Â°C and 400 kPa, at which
point the volume is 10 L. The external force on the piston is now varied in such a manner that the
Râ€”l34a Slowly changes in a polytropic process to 900 kPa, 40Â°C. A. Calculate the work in k] and Show it with the correct Sign by our convention. (18 pts) B. Is the work done on or by the system? (2 pts) 01) 3334a l _. V 3
Pl: LlOO kpa m â€”â€”r 0.010â€:
"â€˜ V 0.0339; "4%
lâ€˜ .: 30Â°C ;
W)..â€” 18 . â€œâ€˜1â€™
V. = 'DLâ€˜: 3,010 m3 (Talk 4'13) S 28? W0 k} V. = 00513? â€œSM (PmCess T 
Mali 1 WE Wâ€œ: . (R V." = E v,â€œ
Pa: 300 klâ€™oe .Axp;+ngn17â€˜=,Â£mâ€™g â€œï¬‚irtVa.
â€˜3 =â€” :0 Â°C m3 Mimi/7414K) r in (Hi/at)
a: â€” .0233? A? (TdÃ© 44$ n .â€” 191403110,
1 : my: = 0â€˜33?â€œ 9â€˜88 ï¬loâ€”â€˜3)(0. 023235 Iâ€ (Vâ€™Aâ€™Q
' â€˜l' 30 8 uc/cfsâ€™m3 :21 ï¬‚ = 1M $747Â»
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 Spring '06
 Notsure
 Thermodynamics, pts, MEEN, special polytropic process, A. energy C., A. T,P,H C.

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