What happens to the internal en(; l7tn tu)q6 yt:w7rbe a.qvbg:r7vafu,mv1 ergy of water vapor in the air that condenses on the outside of a cold glass of water? Is work:turq ;nu ay7 b6b:tqg1vt.r7 vva),l7 m wef( done or heat exchanged? Explain.

Use the conservation of energy to explain why the temperature of a gas43ubrw(87xy bowe9m kua7q7g increases when it is quickly compremyg(38u xe 4okw7779 abrqbwussed — say, by pushing down on a cylinder — whereas the temperature decreases when the gas expands.

In an isothermal process, 3700 J of work is done by ahd)i2 4h6 s5an 0pkmezn ideal gas. Is this enough information to tellapk 4d)m i60en2s h5zh how much heat has been added to the system? If so, how much?

Is it possible for the temperature of a system to remain constant even though hdy;h9xe)14b qt wq1r seat flows into or out ofr4xt q; q)91w1shbey d it? If so, give one or two examples.

Explain why the temperature of a gas incre2s qple n6+ hl-me2kwtc; :u-mases when it is adiabatically compresscu-qew sel-2k:2+ntp ;lhm 6med.

Can mechanical energy ever be transformed completely into heatlv lu uud44sig2zk84(d+vsg- or internal energy? Can the reverse happen? In each case, if your answer is i+v8s(24 v dg-l lg4suudkuz4no, explain why not; if yes, give one or two examples.

Can you warm a kitchen in winter by leaving the oven door open? Canar ;w lmkm0u,dj7+;1aig h*ac x1uokm w9 2al. you cool the kitchen on a hot summer day by leaving t c2w,ljk1 0.1;i;lm+*ram gkwouadu a a x7h9mhe refrigerator door open? Explain.

Would a definition of heat engine 8xi alnn( x-c(efficiency as $e=W/Q_L$ be useful? Explain.

What plays the role of high-temperature and low-temp,,nsi pd 66 ceq2we*puxv1sq )erature areas in (a) an internal combusdu,swe*i6) x2ppcq1 q s vne6,tion engine, and (b) a steam engine?

Which will give the greaternav qu:zh6-zy,oy8wpy)p; 2j improvement in the efficiency of a Carnot engine, a 10:hwyq)yuoazzy; j6v p-8p,n2 $C^{\circ}\,$ 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 th)ql rn+898lm nfpl2ws0qfca : ; sbc/dermal (internal) energy. Why, in general, is it not possible to put this ed9 :nn 8) q2/mpf0c;lqsrlacfb8wl+s nergy to useful work?

A gas is allowed to expand (a) a:e9*v9jr r tzz0z1vfddiabatically and (b) isothermally. In each process, does the entropy increase, decreasf d:trj0zv* 9 9revz1ze, or stay the same? Explain.

A gas can expand to twili uw.x3* uuxfk e4 10hq*fpo.ce its original volume either adiabatically or isothermally. Which process would result in 4.u30fi* 1uulx*of pqxk.he w a greater change in entropy? Explain.

Give three examples, other than those mentionedcs8it/6 li5zwq l-l(o in this Chapter, of naturally occurring processes in which order goes 56qizo/ci8 llsltw- ( to disorder. Discuss the observability of the reverse process.

Which do you think has the greater entropy, 1 kg of solid iron or 1 kg of liqu4 bsqnz::l/ 2ig iu31iehzx0 vcl7t(vid irzili/7gzvuin34c0b q lh(vt:x2s e1: on? Why?

(a) What happens if you remove the lid of a bottle containing chlorine*afhs ; mw:ay* gas? (b) Does the reverse process ever happen? Why or why not? (c) Can you thi* y*am hws:;fank of two other examples of irreversibility?

You are asked to test a machine that the inventor calls an “in-k( yoxo/3m4oo7m- pc xkel+- mroom air conditioner”: a big box, standing in the middle of the room, with a cable that plugs into a power outlet. When theoe7m(x -op-x 3mo+koyml/c4k 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 processes (other than those already mfs kl1w2fy c+8entioned) that would obey the first law of thermodynamics, but, if they actualf +c8y2 ks1fwlly occurred, would violate the second law.

Suppose a lot of papers are strewn all over the floor; then e4 w+rd(/g7mza v(mms you stack them neatly. Does this violate the seconder v( /+4m sdaw7zg(mm law of thermodynamics? Explain.

The first law of thertpjs/k v (aj7;modynamics is sometimes whimsically stated as, “You can’t get something for nothing,” and the second law as, “You can’t even break even.” Explain how these statements could be equivalent to the formaka v7tspj/j;( l statements.

Entropy is often called “time’s arrow” because it tells us in which dif:hon n8j2(.pd b1gmjh)gva 37xa, hlrection natural processes occur. If a movie were run backward, name some processej2,pan md)a8:.(gj g7 hbv1x fho nhl3s that you might see that would tell you that time was “running backward.”

Living organisms, as they grow, convert relatively simple food molecules into fx:.7ew0.6n zuso bpz a complex structure. Is this a violation of the sec6:es0ouz b7.x.wf zpnond law of thermodynamics?

  An ideal gas expands isothermally, perfcy5ll t-g( n g5*;achcorming $ 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 frictionle76*gbt i()am2we chp7fof ;byss piston and maintained at atmospheric pressure. When 1400 kcal of heat is added to the gas, the volume is observeafe*f6 7o;g 7mybc)p (wi2t bhd 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 co uiutqo+i( ir:x*7fk7j0 ca6ioled at constant pressure until its volume is halved, and then it is allowed to expand isothermally back to i(r6ca 7fi:ikjo7t+* ix u0 quits original volume. Draw the process on a PV diagram.

Sketch a PV diagram of the follo+jizwp)g :*t/xf o5 xniu:t5qwing process: 2.0 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.nz)i + ju:fg/pto*5i:txwxq50 L, whereupon the pressure is increased at constant volume until the original pressure is reached.

A 1.0-L volume of air initiah0 op-cjpa;p(lly at 4.5 atm of (absolute) pressure is allowed to expand isothermally until the pressure is 1.0 atm. It is then compressed at constant pressure to its initial volume, and lastly is brought back to poa 0;-(hpj cpits 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 half slowly, whil/xn:j4k4z:vgw :opaf.d b (kfe being kept in a container witjf f:k ::a v/.nwgp(bkzxo4d 4h rigid walls. In the process, 265 kJ of heat left 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 is compressed adiabatically to half itsi ;2x n cfgn2g8(/laga 9jrx3k volume. In doing so, 1850 J of work is don;2/n jgfxagx r 2k3(9gc nali8e 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 toix 3av 1whkwz+s(n66ggi b91a tal pressure of 3.0 atm from 400 mL to 660 mL. Heat th+(wb 6gsa1xa91zi 3gk wn6i vhen flows out of the gas 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 idemfgx1 1 )atzfvyuk:49 al monatomic gas expand adiabatically, performing 7500 J of work in the process. What is the change in temmg)94y1 ukvzx 1t af:fperature of the gas during this expansion?   $ K$

  Consider the followin w(ak19epiq +qjqlz 7-g two-step process. Heat is allowed to flow out of an ideal 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 o7j(qpzk+qq il91-w ae riginal 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. 15–2a;1lsd0n/y li 3 shows two possible states of a system containing 1.35 moles of a monallyna/ ;i 1sd0tomic 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 cuu2b deim,x9n.rved path in Fig. 15–24, the work don me.2in ,9uxbde by the gas 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 state c along the cur- j3lo; e4mu2lcy9 q.x+kr,g jp-plh; qvcfe :ved path shown in Fig. 15–24, 80 J of heat leaves the system and 55 J of work is done on the systp;l9 v;y j.ml2q4o-3jerc: e+cfh,p lkxgu -qem.
(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 15–8 transform if inste aci9kvnc7, o6ad of working 11.0 h she took a noontime bon6v9i,c k a7creak and ran for 1.0 h?    $ \times10^{ 7}J$

  Calculate the average metabolic rnu4tt ,6c(9yps;;qni 6( qhtjzav n* jate 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 h, play;*tq t6a (huj(6,i;y j zp4nnqcnts v9s tennis 1.5 h, and runs 0.5 h daily.    $W$

  A person decides to lose weight by sleeping ou1j8fvx i +e.dfvb0x 7ne hour less per day, using the time for light activity. j. 0fuv+f7v8bidx e1xHow 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 he1sxw cx-;u( l crh-w*r.xz1inat while performing 3200 J of useful work. What is the efficiencl -wcxcw*n-1.u;x z 1h(xisrr y of this engine?    %

  A heat engine does 9200 J of work per cycle while absorbing 22.0 kcal of heat frga +)xcu2q to jg013 aeby5q5pom bput21jaeqq gyox+a) 355 c0g a high-temperature reservoir. What is the efficiency of this engine?    %

  What is the maximum efficiency of a heat engine whose operating temperatures no7efc136w(dxky cyz ku sqp08rr(7 2are 580ydey3ksk06cf 7p(n(qo 2x71w8zr rcu $^{\circ}\,C$ and 380$^{\circ}\,C$?   %

  The exhaust temperature of a heat engine is +e-ere0yk;:z1kbrcd 230$^{\circ}\,C$. What must be the high temperature if the Carnot efficiency is to be 28%?    $^{\circ}\,C$

  A nuclear power plant opera c58de qa)wz- -mi2-goce)hlptes at 75% of its maximum theoretical (Carnot) efficiench2d ae -)qm5lp-)igz oce8wc-y 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’s hot environment be hotter u -a6b v7yos5vc3v;esthan ambient temperature. Liquid nitrogen (77 K) is about as cheap as bottled water. What would be the efficiency of an engine that made use of heat transferred from air at room temperature (293 K) a7e vc 5 ;suyvso-6b3vto the liquid nitrogen “fuel” (Fig. 15–25)?    %(Round to the nearest integer)

  A Carnot engine performs work at the rate of 440 kW wjc)yfy m0m b*6hile using 680 kcal of heat per secfmj )y* yb6mc0ond. If the temperature of the heat source is 570$^{\circ}\,C$, at what temperature is the waste heat exhausted?    $^{\circ}\,C$

  A Carnot engine’s opera *6jtqxn)g2or ting 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 5509+zelg-b1n p dm4i;lv MW of electric power. Estimate the heat disch l1-+mnglbd4v9e ;izparged per second, assuming that the plant has an efficiency of 38%.    $MW$

  A heat engine utilizes a heat soc,fvcn a/8, rii ev.6md+ cp+nurce 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 its heat at 35:)l:4bh(zq o,qsaxa q0$^{\circ}\,C$ 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 engyv bk;i y:n;l4n q grek.x:1+rines work in pairs, the output of heat from one being the aprvky+ q y;1:x:nr in.ebklg;4proximate heat input 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 coil5jat wt6zac l4a,0ph7 is -15$^{\circ}\,C$ and the discharge temperature is 30$^{\circ}\,C$. What is the maximum theoretical coefficient of performance?   

  An ideal refrigerator- cfby*b0m; tio,b)fp.freezer operates with a in a 24$^{\circ}\,C$ room. What is the temperature inside the freezer?    $K$

  A restaurant refrigerator h(fy5x6f )yas,slr tw9 wn 1(dsas a coefficient of performance of 5.0. If the temperature in the kitchy xt y51fsf a,6r(l)n(s9wwd sen outside the refrigerator 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 lui06qyl5dg ,-pg3dm a house warm at 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-;0c; p)qjinp5sgh oz 0$^{\circ}\,C$ 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 has an efficiency of 35%. If it were possible to 6qyhrj3)j-r)w zgh) trun it backward as a heat)qr h- j3)j)hrztg6w y pump, what would be its coefficient of performance?   

  What is the change in l bj-n;v-y jq.7h, hee+tndz,av, +bp entropy of 250 g of steam at 100$^{\circ}\,C$ when it is condensed to water at 100$^{\circ}\,C$?    $J/K$

  One kilogram of water is heate,y( kauemh58palu/2m d from 0$^{\circ}\,C$ to 100°C. Estimate the change in entropy of the water.    $J/K$

  What is the change in e6m.i7 akc:xfzsy+d0 entropy of $1\,m^3$ 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 s hajnlbxbp 3(qp -(x36peed of $3.0m/s$ 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 5/tqj:flt hl2 the ground and coming to rest. What is the total change inf2 tt: /5ljqlh entropy of the rock plus environment as a result of this collision?

  An aluminum rod condu bn, 131r/lp(smi4w:ywsjaej cts $7.50\,cal/s$ 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 30(wfu+xt4 l5 gv$^{\circ}\,C$ 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 alus(q)l9,awdgo -; xrpeminum 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 reservoirs at 970 K and 650 K +f c n795nqq1 dvdus8rproduces 550 J of work per csq c85n9vru7+d f1q ndycle for a 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 two dice, of obtainingvnyat- s2w0zetk 53p +
(a) two numbers totaling 5. The probability is 1/  
(b) two numbers totaling 11. The probability is 1/  

Rank the following five-card hands in order of increasing probability: (a) f 5nldswywwc -x (2)hq 3lgvp5w1 un7-zour aces and a king; (b) six of hearts, eight of diamonds, queen of clubs, thw1xh-w5v -y(wl735gncdq luns ) 2pwzree of hearts, jack 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 droiyf1zfr+uuj 4g3, l 6bp them on the floor. Construct 3ufiu+r yj,4b gl1zf6 a table showing the 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 proyj3m, 8f2zm- hmz nfg*duce about 40 W of electricity per square meter of surface area if directly facing the Sun. How large an area is required to supply the needs ofj8z3zgfnf2h -mym ,m* 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 water to a high resen fc7wancmzt2 w+k ui 6,*q7+brvoir when demn k,6qz7f cbat m+2n7w*iuw+cand 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 artifi1,)hh g+vwp5 qtj8lx) x)lr 03jvv kapcial lake created by a dam (Fig. 15–27). The water depth is 45 m at the dl)0v qjh vhwjl8 ,x)tpgkp3x r5v+1 )aam, 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 anqb1 0+il3tta:qa7mbboc tjl;x x1 y96d built an engine that produces 1.50 MW of usable work while taking in 3.00 MW of thermal energy at 425 K, and rejecting 1.50 MW of thermal energy a1qymit0bxt3 ab79+ q6ol1jlx ba :c;tt 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 enginet4(g5 9sxizinl d4*hp has an efficiency of 0.25 and delivers 220 J of work per cycle per cylinder.p4stdi lg4n95( xz*ih When the engine 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 revers2wywtwpt;9m oj8 4* d8dyuzu)e of a Carnot engine) absorbs heat from the freezer compartmz ww8 tup8mt )oy4y92;judwd*ent 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 develop,tw uf-raux,5 ed that made use of the temperature difference between water at the surface of -5w u,at, fxurthe 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 opposiux02- 1boud-3 bperkw++nrd mjq0,zate directions when they collide and are brought to rest. Estimate the change in entropy of the universe as a result of this collisionjq0p+ 0dr,ozuda kw- 31x e+urm-nb2 b. Assume $T\,=\,20^{\circ}\,C$    $J/K$

  A 120-g insulated aluminut glp+2tjukb9hh 7qbu l:109xb p6jf; m cup at 15$^{\circ}\,C$ 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 coefficient of performance of an ideal heat pump that exn rwzr aiy n5s d:8k/s-5t9z*stracts heat 8*z9sny i-ss a5 zn/wt 5:rrdkfrom 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 ikvm1 h 0/t3lzcar releases 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 lowerb;72 n0nma. 8 bbt0x qsaixrl5 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 (q.1li/emgs9 xw ml h(C in Fig. 15–28 for each of the following processes: (a) ADC, (b(m 19legwi hq.sx(m/l) ABC, and (c) AC directly.

  A 33% efficient power plant puts out 850 MW of electrical power. Cooling towers w(,z bvjgkk47 are used to take away the exhaust heat. gb(zv k47jkw ,
(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 ddo1m x6m h.*a+ 3bqemvelivers energy at 980 MW using steam turbines. The steam goes into the turbines superheated at 625 K and deposits its unused hea m3dq6o m1xmveh* .ab+t in river water at 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 operates at about 15% efficiency. Assume the e8 ttk2 l6 ge()r utabzk:*d)ewngine’s water temperature or8e w)2tg 6*zl d(a tbu:k)ketf 85$^{\circ}\,C$ 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 tallfn9)ypkfviv; )7ksq * cylindrical 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 fat rhn1m,9y(os5tx mk yr 9esults 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 temperature inside a+kpt 1/2f8ebskmbkxd0 o*t0z 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 h-rums -qo 5d0a “refrigerator 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 water 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 condes0-d5hq-m ruo nsation 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