GENERAL PHYSICS II PHYS 260 EXAMINATION II CONCEPTUAL The COMBUSTION of mf grams of a LIQUID HYDROCARBON FUEL occurs in a small combustion chamber immersed in a water bath Mw cw and enclosed in a container mass Mk with specific heat capacity ck The combusti n efficiency is eC As a result of the combustion process the temperature of the WATER BATH CONTAINER SYSTEM increases by T 1 Assuming the efficiency of the combustion process is eC the system is isolated from HEAT TRANSFERS with the surroundings and neglecting any effects associated with the combustion chamber the HEAT of COMBUSTION Lc cal g of the fuel is A Mwcw T B eC Mwcw Mkck T C D E Mwcw Mkck T eC mf eC Mwcw Mkck T mf Mwcw Mkck T mf MAKING ICE 2 M grams of 100oC steam is transformed into solid ICE at 10oC In terms of the liquid and solid specific heat capacities Cliquid Csolid the heat of vaporization LV and the heat of fusion LF the CHANGE in INTERNAL ENERGY ETH of the water during the 100oC STEAM to 10oC ICE transformation change of state is NOTE The boiling temperature of water is 100oC the melting temperature ETH MLV M Cliquid 100 0 MLF M Csolid 10 0 ETH MLV M Cliquid 0 100 MLF M Csolid 0 ETH MLV M Cliquid 100 0 MLF M Csolid 10 0 ETH MLV M Cliquid 0 100 MLF M Csolid 10 0 ETH MLV M Cliquid 0 100 MLF M Csolid 10 0 3 The NET HEAT TRANSFER Qi f required to accomplish the 100oC steam i to 10oC ice f change of state is Qi f ETH Qi f ETH Qi f e ETH where e is the efficiency of HEAT TRANSFER Qi f ETH e where e is the efficiency of HEAT TRANSFER Cannot be determined from the information presented 0oC 10 A B C D E A B C D E 4 n moles of an ideal gas is confined to a piston cylinder assembly the mass of the piston is M and the cross sectional area is A Atmospheric pressure is p0 g the acceleration due to gravity If the temperature of the gas is T from which one of the following expressions based on the principle of equilibrium is the value of L determined A B C D E p0 Mg nRT AL p0 nRT AL Mg A p0 Mg A nRT AL p0 nRT AL Mg A nRT AL A THERMODYNAMIC CYCLE STATE and FIRST LAW ANALYSIS n moles of an ideal monatomic gas is contained in a piston cylinder assembly and is constrained to undergo the thermodynamic cycle displayed on the accompanying p V diagram NOTE p2 mp1 m 1 V3 rV1 r 1 5 p3 V3 T3 ETH 3 A B C D E A B C D E mp1 rV1 T1 ETH 1 mp1 rV1 mrT1 ETH 1 mp1 rV1 mrT1 mrETH 1 p1 rV1 rT1 rETH 1 mp1 rV1 m r T1 m r ETH 1 W2 3 r 1 p1V1 W2 3 m r 1 p1V1 W2 3 1 r p1V1 W2 3 m p1V1 W2 3 m 1 r p1V1 6 For process 2 3 7 For process 4 1 8 For the ENTIRE CYCLE A B C D E A B C D E A B C D E A B Q4 1 W4 1 ETH 4 ETH 1 Q4 1 W4 1 ETH 4 ETH 1 Q4 1 W4 1 ETH 4 ETH 1 Q4 1 W4 1 ETH 4 ETH 1 Q4 1 W4 1 0 ETH 4 ETH 1 Qcycle 0 Wcycle 0 ETH cycle 0 Qcycle Wcycle ETH cycle 0 Qcycle 0 Wcycle ETH cycle 0 Qcycle Wcycle ETH cycle 0 Qcycle Wcycle ETH cycle Q1 2 Q2 3 Q3 4 Q4 1 Q1 2 0 Q2 3 Q3 4 0 Q4 1 Q1 2 Q2 3 Q3 4 Q4 1 Q1 2 Q2 3 Q3 4 Q4 1 Q1 2 Q2 3 Q3 4 Q4 1 W2 3 Q1 2 Q2 3 W2 3 W4 1 Q1 2 Q2 3 Q3 4 Q4 1 10 The efficiency of the CYCLE for the conversion of INPUT HEAT ENERGY to NET MECHANICAL ENERGY OUTPUT is 9 Regarding HEAT TRANSFERS which one of the following statements is TRUE C D E W4 1 Q1 2 Q2 3 W2 3 W4 1 Q1 2 Q2 3 None of the above REMINDER W4 1 for example is the absolute value of W4 1 Consider the composite THERMODYNAMIC DEVICE where a fraction of the WORK output W W1 W2 from two TANDEM THERMAL ENGINES operates a REFRIGERATION UNIT Coefficient of Performance K In addition due to heat transfer losses only a fraction of the heat output from ENGINE 1 is available to operate ENGINE 2 Q3 k Q2 where 0 k 1 11 Which ONE of the following statements is FALSE k Q2 W2 Q4 W Q6 Q5 W 1 k 2 1 1 Q1 K Q5 W W2 2 Q3 K 1 1 k 2 1 1 Q1 K 1 1 k 2 1 1 Q1 K 1 1 k 2 Q1 K 1 k 2 Q1 K 1 1 2 1 1 Q1 A B C D E A B C D E 12 The HEAT TRANSFER Q6 to the HIGH TEMPERATURE RESERVOIR is The DIAGRAM displays the basic HEAT EXCHANGES associated with a GROUND SOURCE HEAT PUMP GSHP Assume the GSHP operates at 50 of the performance level of the corresponding CARNOT HEAT PUMP 13 The DIAGRAM represents the operation of the GSHP during A WINTER HEATING SEASON B C SUMMER COOLING SEASON Cannot be determined from the information presented 14 The COEFFICIENT of PERFORMANCE of this GSHP is A 0 50 TH TH T0 0 50 TH TH TG 0 50 TG TH TG 0 50 T0 TH T0 0 50 TG TG T0 B C D E A B 15 QG QH QN C D E 1 QN 1 QN 1 QN REMINDER Place ANSWERS on a 3x5 notecard and be prepared to transcribe those ANSWERS to the ANSWER GRID on the front cover page of EXAM II and to submit the 3x5 notecard NO 3x5 NOTECARD NO CREDIT
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