What happens to the internal energy of water4k k zah8956k q6jtudf vapor in the air that condenses on the outside of a cold glass of water?zajq956 8h f kdkku4t6 Is work done or heat exchanged? Explain.

Use the conservation of energy to explain why bqmy/rx5 7 8ak*5 esvothe temperature of a gas increases when itxv/ebo qr78k 5ay* ms5 is quickly compressed — say, by pushing down on a cylinder — whereas the temperature decreases when the gas expands.

In an isothermal process, ,xy0ykjh,7 zh3700 J of work is done by an ideal gas. Is this enough information to tell how much heat has been addez ,y 07hxkyj,hd to the system? If so, how much?

Is it possible for the t.a+rjvbw /*uf09xni eks axix1fz53 csi/ g8* emperature of a system to remain constant even though heat flows into or out .3juixivswg*/* abe8ni kr9xa5 +xzfsc 1/f0of it? If so, give one or two examples.

Explain why the temperature of a gas increases when it is adi2(l n94mnyw5sgj w y9sabatically compresswgy9n w l s5y42sn9jm(ed.

Can mechanical energy ever be transformed completely into heat qg)ga ::gyec4 x.9 g(:roxyqaor internal energy? Can t:xe (og::).q4ggra9 yqcg yxa he reverse happen? In each case, if your answer is no, explain why not; if yes, give one or two examples.

Can you warm a kitchen +agub-;s -7 la8 9y yrnutuh an5.q)ziin winter by leaving the oven door open? Can you cool the kitchenu8uai yytan+-u5).zg-rl 7h9;abqs n on a hot summer day by leaving the refrigerator door open? Explain.

Would a definition of heat engine efficiend,.)g, o;vkxywt;kl ucy as $e=W/Q_L$ be useful? Explain.

What plays the role of high-temperature and low-temperature areas in (+8u. fryq :axna) an internal combustion engine, and ( .a8nqf +uyrx:b) a steam engine?

Which will give the greater improvement in the efficiency of a Carnothkos44-t :o6s6 xxa ni-ne 0zfujo: .u engine, a 10 t oj-xsn6x:oe6n 0s.kfz: u-4 ha4iu o$C^{\circ}\,$ increase in the high-temperature reservoir, or a 10 $C^{\circ}\,$ decrease in the low-temperature reservoir? Explain.

The oceans contain a tremendous amount of thy;5hl9r7me6 w 3pldkpermal (internal) energy. Why, in general, is it not possible to put this energy to useful work?l dewm 59 h3;klpr7py6

A gas is allowed to expand (a) adiabatically and (b) isotherm gi fw1t3):g2b +s1vmt6ftmypgfik+ 7ally. In each process, does the entropy increase, decrease, or stay the same? Ex1 b pfgtwt)f+k:2s16gitgmy ivm+3f7plain.

A gas can expand to twice bxn g/.76a6yz+k gdyghs 5-pmits original volume either adiabatically or isothermally. Which process would result in a greater change in entropy? Explaixam y/z6.-bd 76y+5hggsk p gnn.

Give three examples, other than those ment gswed-,dcs l--zr7h6 ioned in this Chapter, of naturally occurring processes in which order goes to disorder. Discuss the, dez7r-cl dws- -sh6g observability of the reverse process.

Which do you think has t:nnjwl rio; 90he greater entropy, 1 kg of solid iron or 1 kg of liquid wno9 :lrj;n0 iiron? Why?

(a) What happens if you remove the lid of a bottle containing chlorine gas? (b) chc7; /*ia89 a7w p7imhj jae*ih sod-Does the reverse process ever happen? Why or why not? (c) Can you think 87 cih*aws7 d jm/*;hiic 7e9hoa- japof two other examples of irreversibility?

You are asked to test a machine that thjb 8hnqs 1shrxrda,g7e1g8ow2s (j.- hwz4j; e inventor calls an “in-room air conditioner”: a big box, standing in the middle of the room, with h21 (j8w1rqae;s ,wonjb 48 rhgg jh-sd7xs z.a cable that plugs into a power outlet. When the machine is switched on, you feel a stream of cold air coming out of it. How do you know that this machine cannot cool the room?

Think up several procesy,t0 y5 (db.ftcjbf/o ses (other than those already mentioned) that would obey the first law of th y/0c,yb5(tft fdo. jbermodynamics, but, if they actually occurred, would violate the second law.

Suppose a lot of papers are strewn all over the flooobvypcj+wnl+tmtp.;) r2 9 a0r; then you stack them neatly. Does this violate the sec09; ppyr)+aw+obclj2 mvt .nt ond law of thermodynamics? Explain.

The first law of thermodynamics is sometimes wi0ixw6 iof( .thimsically stated as, “You can’t get something for nothing,” and the second law as, “You can’t even breaki.0f w(i6 oxit even.” Explain how these statements could be equivalent to the formal statements.

Entropy is often called “time’s arrow” because it tel qbeb4ucd j6 335vse-nls us in which direction natural processes occur. If a movie were run backward, name some processes that you might see that would tell you that time was “running3e56ub bjes4cqn- 3 dv backward.”

Living organisms, as they grodfmksk -p r8.nnc97,hw, convert relatively simple food molecules into a complehndrp9nk-,kmf 8 sc7 .x structure. Is this a violation of the second law of thermodynamics?

  An ideal gas expands itp2o;c6 cp, lvsothermally, performing $ 3.40\times10^{ 3}J$ of work in the process. Calculate
(a) the change in internal energy of the gas,
(b) the heat absorbed during this expansion.    $J$

  A gas is enclosed in a cylinder fitted with a light frictiop dmv(/zpw lcu:9k(uns.v m2* nless piston and maintaine9s m(k2.vunu( :wp/ld*z cp mvd at atmospheric pressure. When 1400 kcal of heat is added to the gas, the volume is observed to increase slowly from $12m^3$ to $18.2m^3$ Calculate
(a) the work done by the gas .   $ \times10^{5 }$
(b) the change in internal energy of the gas.    $ \times10^{ 6}$

One liter of air is cooled atn g1/z/cv j8 8plq7xhh constant pressure until its volume is halved, and then it is7jg//8 hvn1xp8c qhlz allowed to expand isothermally back to its original volume. Draw the process on a PV diagram.

Sketch a PV diagram of the following process: 2.3(a ) reinegp uusoy193: d+qg0 L of ideal gas at atmospheric pressure are cooled at constant pressure to a volume of 1.0 L, and then expanded isothermally back to 2.0 L, whereupon the pressure is increased at constant volume until the original presseuogg:3n d qyi+3a 19puer()sure is reached.

A 1.0-L volume of air initialm ke k m,2m 1 +i6j um/(znd*kdplspyra,,:h)wly at 4.5 atm of (absolute) pressure is allowed to expand isothermally until the presskk2dsdp: z (*+mawj,)nek h 1imp,url,mym 6/ ure is 1.0 atm. It is then compressed at constant pressure to its initial volume, and lastly is brought back to its original pressure by heating at constant volume. Draw the process on a PV diagram, including numbers and labels for the axes.

  The pressure in an ideal gas is cut in halfwf v/72hg )24daeohpq7vpv3j slowly, while being kept in a container with rigid walls. In the process, 265 kJ of heat phw/ogpve v v 22hjqa7)4f3d 7left the gas.
(a) How much work was done during this process?    $J$
(b) What was the change in internal energy of the gas during this process?    $kJ$

  In an engine, an almost ideal gas 9rx 5wxdxv*m8sbgz:;is compressed adiabatically to half its volume. In doing so, 1850 J of wor xm g;d8s *wvxxz:b95rk is done on the gas.
(a) How much heat flows into or out of the gas?    $J$
(b) What is the change in internal energy of the gas?    $J$
(c) Does its temperature rise or fall? ----待选择----fallrise 

  An ideal gas expands at a constant total pressure of 3.0 atm fromexzwg j9f 804u0zeun, 400 mL to 660 mL. Heat then flows out of the ga80x4uef0zue 9,jgnw z s at constant volume, and the pressure and temperature are allowed to drop until the temperature reaches its original value. Calculate
(a) the total work done by the gas in the process,   $J$
(b) the total heat flow into the gas.    $J$

  One and one-half moles of an ideal monatomic gas expand adiabatically,u rz2.haj;sd ; performing 7500 J of work in the process. What is the change in temperaturea ;.dz uj2s;rh of the gas during this expansion?   $ K$

  Consider the following two-step prgwtc j i2:y5 le7a+i+rocess. Heat is allowed to flow out of an idealily+5e +7 j:crig2w ta gas at constant volume so that its pressure drops from 2.2 atm to 1.4 atm. Then the gas expands at constant pressure, from a volume of 6.8 L to 9.3 L, where the temperature reaches its original value. See Fig. 15–22. Calculate
(a) the total work done by the gas in the process,    $J$
(b) the change in internal energy of the gas in the process,    $J$
(c) the total heat flow into or out of the gas.    $J$  ----待选择----intoout  the gas

  The PV diagram in Fig. 15–23 shows two possible states of a system containing 1.v; 44svx d+ye,vrug0ikzk1xuj nksf /*/ r.:f35 molu/ ,4:vxvj+sk .v gk1;4zduf/ie* xsnrkfry0 es of a monatomic ideal gas.$(P_1\,=\,P_2\,=\,455N/m^2,V_1\,=\,2.00m^3,V_2\,=\,8.00m^3)$
(a) Draw the process which depicts an isobaric expansion from state 1 to state 2, and label this process A.
(b) Find the work done by the gas and the change in internal energy of the gas in process A. W =    $J$ $\Delta\,U$ =    $J$
(c) Draw the two-step process which depicts an isothermal expansion from state 1 to the volume $V_2$ followed by an isovolumetric increase in temperature to state 2, and label this process B.
(d) Find the change in internal energy of the gas for the two-step process B.    $J$

  When a gas is taken from a to c along the curved path in Fig.y rt:74 .l:.rdkmy mkh 15–24, the work done by the gas. h7r:ymy4kmltd k:.r is $W\,=\,-35\,J$ and the heat added to the gas is $Q\,=\,-63\,J$ Along path abc, the work done is $W\,=\,-48\,J$
(a) What is Q for path abc?    $J$
(b) If $P_c\,=\,\frac{1}{2}P_b$ what is W for path cda?    $J$
(c) What is Q for path cda?    $J$
(d) What is $U_a-U_c$?    $J$
(e) If $U_d-U_c\,=\,5J$ what is Q for path da?    $J$

  In the process of taking a gas from state a to st6mw ut 5vcxya;fs6f0*ate c along the curved path shown in Fig. 15–24, 80 J of heat leaves th s w6muy6fcfvxt*a;05 e system and 55 J of work is done on the system.
(a) Determine the change in internal energy, $U_a-U_c$.    $J$
(b) When the gas is taken along the path cda, the work done by the gas is How much heat Q is added to the gas in the process cda?    $J$
(c) If $ P_a\,=\,2.5P_d$ how much work is done by the gas in the process abc?    $J$
(d) What is Q for path abc?    $J$
(e) If $U_a-U_b\,=\,10\,J$ what is Q for the process bc?    $J$
Here is a summary of what is given:
$\begin{aligned}
Q_{\mathrm{a} \rightarrow \mathrm{c}} & =-80 \mathrm{~J} \\
W_{\mathrm{a} \rightarrow \mathrm{c}} & =-55 \mathrm{~J} \\
W_{\mathrm{cda}} & =38 \mathrm{~J} \\
U_{\mathrm{a}}-U_{\mathrm{b}} & =10 \mathrm{~J} \\
P_{\mathrm{d}} & =2.5 P_{\mathrm{d}} .
\end{aligned}$

  How much energy would the person of Example 15–8ih4a;6q2tvc3ui (ysa transform if instead of working 11.0 h she took a noontime break and ranu v;qts6i i2yaach(34 for 1.0 h?    $ \times10^{ 7}J$

  Calculate the average mgi;w/ckx+a)s etabolic rate of a person who sleeps 8.0 h, sits at a desk 8.0 h, engages in light activity 4.0 h, watches television 2.0 gw+kci;ax/s) h, plays tennis 1.5 h, and runs 0.5 h daily.    $W$

  A person decides to lose 1 w.-dti(qv, j7owb8t nekrl 0weight by sleeping one hour less per day, using the time for li0jd- w (bkitv.1qont8e7w, lr ght activity. How much weight (or mass) can this person expect to lose in 1 year, assuming no change in food intake? Assume that 1 kg of fat stores about 40,000 kJ of energy.   kg(retain one decimal places)    $lbs$

  A heat engine exhausts 8200 J of heat while perfwje 0*j7m yv*9 uuwrq-orming 3200 J of useful work. What is the efficiency of this enginey-jwmru0e 9j u*w*7qv?    %

  A heat engine does 9200 J of work per cycle while absorbing 22.0 kcal of psyujas(;;+l;qwvyr8) ,by g heat from a high-temperature reservoir. What is the e vsp y;8 ;lgas()qyjy;w+ub, rfficiency of this engine?    %

  What is the maximum efficiency of a heat engine whose operating temperat; ksvcm* sm 29d(jas6eures are ks*m6jc v2ea;(sdms9 580$^{\circ}\,C$ and 380$^{\circ}\,C$?   %

  The exhaust temperature of a heat engly9+ ndgx7yj ;cnz;t- ine is 230$^{\circ}\,C$. What must be the high temperature if the Carnot efficiency is to be 28%?    $^{\circ}\,C$

  A nuclear power plant operates at 75% of v1x 2e fps0hx,its maximum theoretical (Carnot) efficiexfpv02sxh1 e, ncy between temperatures of 625$^{\circ}\,C$ and 350$^{\circ}\,C$. If the plant produces electric energy at the rate of 1.3 GW, how much exhaust heat is discharged per hour?    $ \times10^{13 }J/h$

  It is not necessary that a heat engine’s3n +uaup3wl)/ck s +mp hot environment be hotter than ambient temperature. Liquid nitrogen (77 K) is about as cheap as bottled water. What3/m n)pu +u kal3wc+ps would be the efficiency of an engine that made use of heat transferred from air at room temperature (293 K) to the liquid nitrogen “fuel” (Fig. 15–25)?    %(Round to the nearest integer)

  A Carnot engine performs work at t jbjno*q4duuh/, 39j mhe rate of 440 kW while using 680 kcal of heat per second. If the temperature of th*jbnjd qu4mu,9o3j /he heat source is 570$^{\circ}\,C$, at what temperature is the waste heat exhausted?    $^{\circ}\,C$

  A Carnot engine’s operatdv.p0fujm 1d ;-,exjping temperatures are 210$^{\circ}\,C$ and 45$^{\circ}\,C$. The engine’s power output is 950 W. Calculate the rate of heat output.    $W$

  A certain power plant puts out 550 MW of electric power. Estimate the hjy/44j gq tqf:jyl0(i eat discharged per second, assumy /yj4:jjt0q qfil4g(ing that the plant has an efficiency of 38%.    $MW$

  A heat engine utilizes a heyv0j jbojj8o,6 sr5 d5at source at 550$^{\circ}\,C$ and has an ideal (Carnot) efficiency of 28%. To increase the ideal efficiency to 35%, what must be the temperature of the heat source?    $^{\circ}\,C$

  A heat engine exhausts illg mh0ipl4eji1;0 it d)ao*;c4)ws rts heat at 350$^{\circ}\,C$ and has a Carnot efficiency of 39%. What exhaust temperature would enable it to achieve a Carnot efficiency of 49%?    $^{\circ}\,C$

  At a steam power plant, steam engines work in pairs, the output of heat from one s,ople65 tmk12 .rgb n9*vz:qrcm+c r being the approximate heat it pcmob +kl61, 5n.g2rvmzr *ec9s:r qnput of the second. The operating temperatures of the first are 670$^{\circ}\,C$ and 440$^{\circ}\,C$, and of the second 430$^{\circ}\,C$ and 290$^{\circ}\,C$. If the heat of combustion of coal is $ 2.8\times10^{7 }\,J/kg$ at what rate must coal be burned if the plant is to put out 1100 MW of power? Assume the efficiency of the engines is 60% of the ideal (Carnot) efficiency.    $kg/s$

  The low temperature of a freezer cooling coils0i7 la/pfv(m is -15$^{\circ}\,C$ and the discharge temperature is 30$^{\circ}\,C$. What is the maximum theoretical coefficient of performance?   

  An ideal refrigerator-freezer operates with zk(. :aq;aw+y89lp uk.hstz a.y q*rga in a 24$^{\circ}\,C$ room. What is the temperature inside the freezer?    $K$

  A restaurant refrigerator hzkc)h:/f 5e j8iib) blquj v,52ec+y ras a coefficient of performance of 5.0. If the temperature in the kitchen outside the ref))uqb 5ch/i i5jf: 8b2elcj+ekv yr,z rigerator is 29$^{\circ}\,C$, what is the lowest temperature that could be obtained inside the refrigerator if it were ideal?    $^{\circ}\,C$

  A heat pump is used to keep a house warm ew0x9 .q1w ox-un 6bbkat 22$^{\circ}\,C$. How much work is required of the pump to deliver 2800 J of heat into the house if the outdoor temperature is
(a) 0$^{\circ}\,C$,    $J$
(b) -15$^{\circ}\,C$ Assume ideal (Carnot) behavior.    $J$

  What volume of water at 0;r3gun 3oxe18dhe: jq $^{\circ}\,C$ can a freezer make into ice cubes in 1.0 hour, if the coefficient of performance of the cooling unit is 7.0 and the power input is 1.0 kilowatt?    $L$

  An ideal (Carnot) engine ha 618jcaa5r1ftgb qo* +ga*dkf s an efficiency of 35%. If it were possible to run it backward as a heat pump, what would be its coefficient of performan 568a*bjkq+cgo*1 ftfagda1rce?   

  What is the change in entropy of 250 g of sten4do82 ttz4hbym/cb+ am at 100$^{\circ}\,C$ when it is condensed to water at 100$^{\circ}\,C$?    $J/K$

  One kilogram of water is heatxz0pbg9rj p4 -0y7bll/mt nk 1ed from 0$^{\circ}\,C$ to 100°C. Estimate the change in entropy of the water.    $J/K$

  What is the change in entropy of wrtvzb3/2 s,r $1\,m^3$ of water at 0$^{\circ}\,C$ when it is frozen to ice at 0$^{\circ}\,C$?   $ \times10^{6 }\, J/K $

  If $1.00\,m^3$ of water at 0$^{\circ}\,C$ is frozen and cooled to -10$^{\circ}\,C$ by being in contact with a great deal of ice at -10$^{\circ}\,C$ what would be the total change in entropy of the process?   $J/K$

  A 10.0-kg box having an initial speed o9s;h;f.v+w6 yemk gmzhz+mx 4f $3.0m/s$ slides along a rough table and comes to rest. Estimate the total change in entropy of the universe. Assume all objects are at room temperature (293 K).   $J/K$

A falling rock has kinetic energy KE just before striking the ground and coming drtqpk95tt14to*i z (:0wjk.uzqvy4to rest. What is the total change in entropy iru:15 o(t.kq*pkjt q90 ztt4dv zy4wof the rock plus environment as a result of this collision?

  An aluminum rod condu+vf-)z; (7kc zqmr ghxcts $7.50\,cal/s$ from a heat source maintained at 240$^{\circ}\,C$ to a large body of water at 27$^{\circ}\,C$. Calculate the rate entropy increases per unit time in this process.   $\frac{J/K}{s}$

  1.0 kg of water at 3-l7 ia9az )xaz/wse2(x/k fcb0$^{\circ}\,C$ is mixed with 1.0 kg of water at 60$^{\circ}\,C$ in a well-insulated container. Estimate the net change in entropy of the system.    $J/K$

  A 3.8-kg piece of aluminum 00 a xz3pvs*cbh5ex/r at 30$^{\circ}\,C$ is placed in 1.0 kg of water in a Styrofoam container at room temperature (20$^{\circ}\,C$). Calculate the approximate net change in entropy of the system.    $J/K$

  A real heat engine working between heat 4em 3b4jg mr o(,oofs/reservoirs at 970 K and 650 K produces 550 J of work per cycle for a r(4ogm3,femo jbs o 4/heat input of 2200 J.
(a) Compare the efficiency of this real engine to that of an ideal (Carnot) engine.    % of ideal(Round to the nearest integer)
(b) Calculate the total entropy change of the universe per cycle of the real engine.    $J/K$
(c) Calculate the total entropy change of the universe per cycle of a Carnot engine operating between the same two temperatures.   

  Calculate the probabilities, when you throw twoyl*y m hnv /aaph -cg2v87bo(5 dice, of obtaining
(a) two numbers totaling 5. The probability is 1/  
(b) two numbers totaling 11. The probability is 1/  

Rank the following fg4kmcg 9o p: 9hxh0op8ive-card hands in order of increasing probability: (a) four aces and a king; (b) six of hearts, eight of diamonds, queen of clubs, three of hearts, j:h8o9ok9p h4g m 0pcgxack of spades; (c) two jacks, two queens, and an ace; and (d) any hand having no two equal-value cards. Discuss your ranking in terms of microstates and macrostates.

  Suppose that you repeatedly shake six coins in your hand and dro-el,;knb 9 *ydg*pqzlvuhh qef,l86g5 1k mj-p them on the floor. Construct a table showing the dl,gymh k1nllvkgpbq ;69-- h z*je5ef ,q8u* number of microstates that correspond to each macrostate. What is the probability of obtaining
(a) three heads and three tails,   /64
(b) six heads?   /64

  Solar cells (Fig. 15–26) can produce about 40 W of electricity per squa0,e yxnq dzk8m; u:ncy/1drf8re meter of surface area if directly fqn d,fn x0d8 k /y:8;zce1yumracing the Sun. How large an area is required to supply the needs of a house that requires $22k\,Wh/day$ Would this fit on the roof of an average house? (Assume the Sun shines about $9h/day$)   $m^2$

  Energy may be stored for use during peak demand by pumping wau:pdm2 ,kmh3oter to a high reservoir whepm2hu:,3kdm o n demand is low and then releasing it to drive turbines when needed. Suppose water is pumped to a lake 135 m above the turbines at a rate of $ 1.00\times10^{ 5}kg/s$ for 10.0 h at night.
(a) How much energy (kWh) is needed to do this each night?    $\times10^{9 }W\cdot\,h$
(b) If all this energy is released during a 14-h day, at 75% efficiency, what is the average power output?    kW

  Water is stored in an artificial lake created by a dam (Fig. 15–27). The water xff0e f2 .1c: jrl/agndepth is 45 m at tn0/ :l .cgjf1xfae2frhe dam, and a steady flow rate of $35m^3/s$ is maintained through hydroelectric turbines installed near the base of the dam. How much electrical power can be produced?    $ \times10^{7 }W$

  An inventor claims to have designed and built an engine that produces 1.50 Mxj1ivs+ 8;w6z;liru fW of usable work while taking in 3.00 MW oiwi 6fuvls+1rz; ;j 8xf thermal energy at 425 K, and rejecting 1.50 MW of thermal energy at 215 K. Is there anything fishy about his claim? Explain.  ----待选择----yesno 

  When $ 5.30\times10^{ 4}J$ of heat is added to a gas enclosed in a cylinder fitted with a light frictionless piston maintained at atmospheric pressure, the volume is observed to increase from $1.9m^3$ to $4.1m^3$ Calculate
(a) the work done by the gas,    $ \times10^{5 }J$
(b) the change in internal energy of the gas.    $ \times10^{5 }J$
(c) Graph this process on a PV diagram.

  A 4-cylinder gasoline engine has an effi;8u d6q pl4x7 yk-u4gknez g8dciency of 0.25 and delivers 220 J of work per cycle per cylinder. When the eulz-6 du;q yg4k en4dx 7gk88pngine fires at 45 cycles per second,
(a) what is the work done per second?    $ \times10^{4 }J/s$
(b) What is the total heat input per second from the fuel?    $ \times10^{5 }J/s$
(c) If the energy content of gasoline is 35 MJ per liter, how long does one liter last?    s

  A “Carnot” refrigerator (the reverse 8qkez5prdst304ew3; t xb ogj5;da4dof a Carnot engine) absorbs heat from the freezer cdez5kg;j s5;3d0r4 tqw43dx8oepb ta ompartment at a temperature of -17$^{\circ}\,C$ and exhausts it into the room at 25$^{\circ}\,C$.
(a) How much work must be done by the refrigerator to change 0.50 kg of water at 25$^{\circ}\,C$ into ice at -17$^{\circ}\,C$    $ \times10^{4 }J$
(b) If the compressor output is 210 W, what minimum time is needed to accomplish this?    s

  It has been suggested that a heat engine could be developed that made use of the).;fjvzmjci+ o gs 4t2 temperature differe)gzc2sj. fo m+ij4;v tnce between water at the surface of the ocean and that several hundred meters deep. In the tropics, the temperatures may be 27$^{\circ}\,C$ and 4$^{\circ}\,C$, respectively.
(a) What is the maximum efficiency such an engine could have?    %
(b) Why might such an engine be feasible in spite of the low efficiency?
(c) Can you imagine any adverse environmental effects that might occur?

  Two 1100-kg cars are traveling in opposite dir,l 326gj4rfccl x*d w/efeg;pections when they collide and are brought to rest. Estimate the change in entropy of the universe as a result of this collision. p;,l/e g jce6l4crd2fx wgf*3Assume $T\,=\,20^{\circ}\,C$    $J/K$

  A 120-g insulated aluminum cup at 1v eqw:e:9t9 rd5$^{\circ}\,C$ is filled with 140 g of water at 50$^{\circ}\,C$. After a few minutes, equilibrium is reached.
(a) Determine the final temperature,    $^{\circ}\,C$
(b) estimate the total change in entropy.    $J/K$

  (a) What is the coefficiextz .2wz8kh 5unt of performance of an ideal heat pump that extracts heat frxkt5wu .2 h8zzom 6$^{\circ}\,C$ air outside and deposits heat inside your house at 24$^{\circ}\,C$?   
(b) If this heat pump operates on 1200 W of electrical power, what is the maximum heat it can deliver into your house each hour?    $ \times10^{ 7}J$

  The burning of gasoline in a car releamwh tn*pr06g;i8k 2anses about $ 3.0\times10^{ 4}kcal/gal$ If a car averages $41km/gal$ when driving $90km/h$ which requires 25 hp, what is the efficiency of the engine under those conditions?    %

  A Carnot engine has a lowerg2+xu qqu -xvesg,a6 hm-ua; . operating temperature $T_L\,=\,20^{\circ}\,C$ and an efficiency of 30%. By how many kelvins should the high operating temperature $T_H$ be increased to achieve an efficiency of 40%?    $K$

Calculate the work done by an ideal gas in going from state A to state C in a8(3c 9rlh-: 2o knb6cj8totecd0nyn Fig. 15–28 for each of the following processes: (a) ADC, (b) ABt j nb0eoo6-nd:c c8239ath8 nrclk(yC, and (c) AC directly.

  A 33% efficient power plant puts out 8l*j67* d 2cyj7yt wybnp ,x9sso(zq. h50 MW of electrical power. Cooling towers are used to take away the exha*j *xlb7dphy(tno s ,.9csq6wyy 2 zj7ust heat.
(a) If the air temperature is allowed to rise 7.0 $C^{\circ}\,$, estimate what volume of air $(LM^3)$ is heated per day. Will the local climate be heated significantly? $\approx$   $km^3/day$(Round to the nearest integer)
(b) If the heated air were to form a layer 200 m thick, estimate how large an area it would cover for 24 h of operation. Assume the air has density $1.2kg/m^3$ and that its specific heat is about $1.0KJ/kg\cdot\,C$ at constant pressure.    $km^2$

  Suppose a power plant dehb y;d(ac:o h fk+2 4nq9;wgumlivers energy at 980 MW using steam turbines. The steam goes into the turbines superheated at 625 K and deposits its unused heat in river water au q(oacm;kdh w4 y29gnh;+f:bt 285 K. Assume that the turbine operates as an ideal Carnot engine.
(a) If the river flow rate is $37m^3/s$ estimate the average temperature increase of the river water immediately downstream from the power plant.    $C^{\circ} $
(b) What is the entropy increase per kilogram of the downstream river water in $J/kg \cdot\,K?$    $J/kg\cdot\,K$

  A 100-hp car engine opera+/yv pin*.*x gdzf. )lecbuf+tes at about 15% efficiency. Assume the engine’s water temperature of 8v+/gf.xipe * *fd).ncbu+zy l 5$^{\circ}\,C$ is its cold-temperature (exhaust) reservoir and 495$^{\circ}\,C$ is its thermal “intake” temperature (the temperature of the exploding gas–air mixture).
(a) What is the ratio of its efficiency relative to its maximum possible (Carnot) efficiency?    %
(b) Estimate how much power (in watts) goes into moving the car, and how much heat, in joules and in kcal, is exhausted to the air in 1.0 h.P =    W $Q_L$ =    $ \times10^{ 9}J$ $Q_L$ =    $ \times10^{5 }kcal$

  An ideal gas is placed in a tall cylinx5qax ,ok,f 2a4eyj4lx1i j q1 05cbhcdrical jar of cross-sectional area $0.800m^2$ A frictionless 0.10-kg movable piston is placed vertically into the jar such that the piston’s weight is supported by the gas pressure in the jar. When the gas is heated (at constant pressure) from 25$^{\circ}\,C$ to 55$^{\circ}\,C$, the piston rises 1.0 cm. How much heat was required for this process? Assume atmospheric pressure outside.    $J$

  Metabolizing 1.0 kg of fau:e; eg4upcbn z++4cp7(b.c,uml n oct results in about $ 3.7\times10^{7 }J$ of internal energy in the body.
(a) In one day, how much fat does the body burn to maintain the body temperature of a person staying in bed and metabolizing at an average rate of 95 W? $\approx$ =    $kg/d$(retain two decimal places)
(b) How long would it take to burn 1.0-kg of fat this way assuming there is no food intake?    d

  An ideal air conditioner keeps the tokz -ar7ipq6,z-w gt b-dj4f v/p8d-cemperature inside a room at 21$^{\circ}\,C$ when the outside temperature is 32$^{\circ}\,C$. If 5.3 kW of power enters a room through the windows in the form of direct radiation from the Sun, how much electrical power would be saved if the windows were shaded so that the amount of radiation were reduced to 500 W?    W

  A dehumidifier is essentially a “r4pzo6 ki,esv:gvo5ohy+v9ah yo3 ;m 5p v96a hefrigerator with an open door.” The humid air is pulled in by a fan and guided to a cold coil, where the temperature is less than the dew point, and some of the air’s water condenses. After this +y9h;ops5 6 oz 3g4vmh,9ae6p5o: iyvk ohva vwater is extracted, the air is warmed back to its original temperature and sent into the room. In a well-designed dehumidifier, the heat is exchanged between the incoming and outgoing air. This way the heat that is removed by the refrigerator coil mostly comes from the condensation of water vapor to liquid. Estimate how much water is removed in 1.0 h by an ideal dehumidifier, if the temperature of the room is 25$^{\circ}\,C$, the water condenses at 8$^{\circ}\,C$, and the dehumidifier does work at the rate of 600 W of electrical power.    kg