What happens to the internal energy of water vapor in the air tf wr88es2qpxe)n/vvdfv, kek)7 p 93dhat condenses on the outside of a cold glass of water? Is work done or heat exchanged? Explai 7xps)vk/8f 8n2dwfvdkvqe, ) r93 eepn.

Use the conservation of energy to explain why the 566jwspo n8o atemperature of a gas increases when it is quick opj6wo86as5nly compressed — say, by pushing down on a cylinder — whereas the temperature decreases when the gas expands.

In an isothermal process, 3700 J of work is d) ms1lhmg2cftrf4ctr u0c /xx;*(8w zone by an ideal gas. Is this enough information to te4tu/x gc fs *rfl;zm rhcc )2x08wmt(1ll how much heat has been added to the system? If so, how much?

Is it possible for the temperature5extsk:t- 0/ga qksu8 of a system to remain constant even though heat flows s0 kq a8:-ktug e5x/stinto or out of it? If so, give one or two examples.

Explain why the temperature of a gas;rb6kcxl0kf vc17.h t increases when it is adiabatically compressekfh60.;1lc bkvcr x 7td.

Can mechanical energy ever 1zd/z pmdyh/1be transformed completely into heat or internal energy? Can the reverse happen? In each case, if your answer is no, explain why/ym zhdz1 1/dp not; if yes, give one or two examples.

Can you warm a kitchen in winter by leakdrp b(6z. xd bpyjv h:x, sp.:fr72r3ving the oven door open? Can you cool the kitchen on a ho:.7 xpd.: spb(dh26 , przbxrkyfrj3vt summer day by leaving the refrigerator door open? Explain.

Would a definition of heat e * 4lijqrn.l )wu+wo.jngine efficiency as $e=W/Q_L$ be useful? Explain.

What plays the role of high-temperature and low-t4f d,p*vie lc5hm++dqemperature areas in (a) an internal combustion engine, and (b) a stq hf 5dvde4l+cm i,+p*eam engine?

Which will give the greater improvement i r3l0c.iognr(1 zpcjzc)j4w6bx7f9tn the efficiency of a Carnot engine, a 1nx ct 4 7j3)6 91b0icrcz(zglfpojrw.0 $C^{\circ}\,$ increase in the high-temperature reservoir, or a 10 $C^{\circ}\,$ decrease in the low-temperature reservoir? Explain.

The oceans contain a tremendous an bm;2 4d0dk3kwfh-jimount of thermal (internal) energy. Why, in general, is it not possible to putm4 ibd;n03dk2f- h wkj this energy to useful work?

A gas is allowed to expand (a) adiabatically and (b) isothermally. In each proc)c-c)w mcmqpxk:+ t -fess, does the entropy incre +t-c)xp f c-wqm:cmk)ase, decrease, or stay the same? Explain.

A gas can expand to twic a,: w5aa0czige its original volume either adiabatically or isothermally. Which process would result in a greater change in entropyza , i:g0w5aca? Explain.

Give three examples, other than those mentioned in this Chapter, of naturally o8x 2ry 3xrsesmv197g yo/9pibccurring processes in which order goes to disorder. Discu/8 y1bxsiser9vg723o rmx9py ss the observability of the reverse process.

Which do you think has the greater entropy, 1 kg of solid iron or 1 ko r6ob0+oo lth e3;(yrg of liquid iron? Why;+6oo( hyo e0r3rlo tb?

(a) What happens if you removas-9i mt*u1 u .et 4h24lb xtl8d8hpvje the lid of a bottle containing chlorine gas? (b) Does the reverse process ever happen? Why or why not? (c) Can you t1mvtulutj 2*l p 4b4.d-8 sthiax89ehhink of two other examples of irreversibility?

You are asked to test a machin t5xq t0aj5iplt:5l1qx2 dj;ye that the inventor calls an “in-room air conditioner”: a big box, standing in the middle of the room, with a cable that plugs into a power outlet. When the machine is switc :xq 55yl2a1tx lj;tij05pdtqhed 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 mentioned) that h(i7b q8p0ukvwould obey the first lawp(iu bq807kh v of thermodynamics, but, if they actually occurred, would violate the second law.

Suppose a lot of papers adwi5e(v guezq)rz704e .al 9ure strewn all over the floor; then you stack them neatly. Does this violate the second law of thermodynamics? Explai(q 047lg5u)weziez r d.vau9e n.

The first law of thery 7dhvb* nb bus;1-k7zmodynamics is sometimes whimsically stated as, “You can’t get something for nothivds1 ; 7b-yh b*nb7zukng,” and the second law as, “You can’t even break even.” Explain how these statements could be equivalent to the formal statements.

Entropy is often called “time’s arrow” because in)x4a ..,d9v vq uunlw437insmg 8 dqet tells 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 “ru9d 7qqvvn.ud x sni84 4gam.l,w u3en)nning backward.”

Living organisms, as they grow, conver7 sgx(;2myp3t/l injh/;fth it relatively simple food molecules into a complex structure. Is this a violation of the second law of thermodyn3 /2m/sp ifn; t;hi( jtyg7hxlamics?

  An ideal gas expands isothermally, p.ctu7g.5 4o o8vvzkuo erforming $ 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 cylinpw t.ts c*u0s:der fitted with a light frictionless piston and maintained at atmospheric pressure. When 1400 kcal of heat is added to the gas, the volume is obt.w:s0tsu*c p served 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 at constant pressure until its vownd9rrs c fn8nj40mie) x40 nxp:r+ z 9.n4kmplume is halved, and then it is allowed to expand isothermally back to its origpiw z0 dn 8n9 :nr)cfrm.mrsn4en0 j494 xpxk+inal volume. Draw the process on a PV diagram.

Sketch a PV diagram of the following process: 2.0 L of idea :4 (n8)9wlw icheimg+lip,yql gas at atmospheric pressure a glh 4+9ici8l:q(m)ey ,npwiwre 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 pressure is reached.

A 1.0-L volume of air iz y)r- 4m qa.kpf7y6lknitially 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 its original pressure by heating at constaq.fyy7kk6a -pz)4mlr nt volume. Draw the process on a PV diagram, including numbers and labels for the axes.

  The pressure in an ideal gada nn6qopk(st mqd 7m*f;a2 3:s is cut in half slowly, while being kept in a container with rigid walls. In the *;m adq26 kq7n d3fm :(taosnpprocess, 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 adpl af 4,h9b g,(o8 )ejtofut/riabatically to half its volume. In doiarbpu( /8 , toohl 4,f9jt)fegng so, 1850 J of work 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 pr3j9+ l) c y1(d: np(uquus mah2ox9cjwessure of 3.0 atm from 400 mL to 660 mL. Heat then flows out of the gas at constant volume, and the p) 9(n(+x:3uc jul 12w9adhqpuom jsycressure 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 adiabati 4x e(q4r-aa1peykr3*jfn g5d cally, performing 7500 J of work in the process. What is the change in tek3 qne j5arex*rp g-(yfa441dmperature of the gas during this expansion?   $ K$

  Consider the followi 5omifvei5j(iivh)s,s6u2ko0kkz m )z46; v ung 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 volum20u6o( v,;ehmi) ki k65 zij5)zsfomi v uk4sve 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 posj) hzq78k;uj by;u3 c vovg3s6sible states of a system containing 1.35 moles of a mon7gh;3j 6ykobquu)zv8j v 3;csatomic 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. 15–24, the workz) 5-ryyv2ew n-nyv9 s done by the g en)zrwn-v vsy52y9y-as 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 tod cmr5dd2vu dw+4kd-9j9 f)yd state c along the curved path shown in Fi+2 vk594urd-y) dfwddd dj 9mcg. 15–24, 80 J of heat leaves the 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 15–8 transform if instead of 6aijx3s 1ni3 i0cpo8xt 1 f3eiworking 11.0 h she too3jp1 txao eii0xi1ic3fn 8 63sk a noontime break and ran for 1.0 h?    $ \times10^{ 7}J$

  Calculate the average metabolic rate of a persodl0)xo.o xk t75eb7sq n who sleeps 8.0 h, sits at a desk 8.0 h, engages in light activity 4.0 h, watches televite.qol0 s dx7bo kx57)sion 2.0 h, plays tennis 1.5 h, and runs 0.5 h daily.    $W$

  A person decides to lose weight by sleeping one ho+jq.fwtem ,/ 29fwqomur less per day, using the time for light activiqoqmm+ w9.w/,tj e ff2ty. 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 whilek gmt ,c/na/e4:plyo/m6 m h.m performing 3200 J of useful work. What is the efficiency mgl/om:n, mam4p/hke/t6 .cy of this engine?    %

  A heat engine does 9200 J of work per cycle whn6:dyk:i 0 x,apm;m/ma mft c/ile absorbing 22.0 kcal of heat from a high-temperature reservoir. What is the efficiency of this engine? t dc6maxf,p k:/yimmn/:;m 0a    %

  What is the maximum efficiency of a heat engine whose operatin i6q yy c5r3rj/)dhwfce+vp63 g temperatures are c3p ) 65q drfj6ivhe3y/c+ywr580$^{\circ}\,C$ and 380$^{\circ}\,C$?   %

  The exhaust temperature of a heat gbdvmnj6-7azw: (m0n engine 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 its maximumf2xa -9awztu- theoretical (Carnot) efficiency between tem watau2 -zxf9-peratures 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 than3lvh iwe, 81p0uc kibm0 t:;mz: lapb, ambient temperature. Liquid nitrogen (77 K) is about as cheap as bottled water. What would be the efficiency of an engine that made up8 ual m0,3 l;v:ihk1b0,ctwzmepi b: se 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 the rate of 440 kW while usi9pcz 8 f fzp5mnc3zc p80vp d58x:gt1fng 680 kcal of heat per second. If the temperature of the hem5pcc3:v zxpngz pf ct98z8dp0518f f at source is 570$^{\circ}\,C$, at what temperature is the waste heat exhausted?    $^{\circ}\,C$

  A Carnot engine’s operating temperatuiq7k;2xd+.z hyiu3l/fos+om /8ji usres 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 tmzr6 2, 4u3srxvjz uw6he heat discharged per second, assuming that the plant has46zsur2r xuj 3z,mw6v an efficiency of 38%.    $MW$

  A heat engine utilizess9.tw h,no) r1l nq v dyyms4bp8n8i4( a heat 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 its he04 w gtcng oov+d a:,+rytai0)at 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 outputowq7c(gfu4+ 2;8vqftl(l ze g of heat from one being the approxima ( vfe24fq87ol;wgq+cgtzu( lte 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 frpyt+ ky5;nl07v ukf2kpl4lzkt4w50 reezer cooling coil 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 a in 3a.vs ez;ju6 ka 24$^{\circ}\,C$ room. What is the temperature inside the freezer?    $K$

  A restaurant refrigerator has a coefficient of performance of 5.0. If the te :e y9ml5qjw.omperature in the kitchen outsideeloqmj 9w:y5 . 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 a house warmdbfg l:s jw yoi863;*:bel )9dhb/nsh 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 kmix9;t*ms *lat 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 jt*b c.m1m4 0ege7qinwere possible to run it backward as a heat pump, what would be its coefficient of p1b.n jeq4m 0gmi7*tc eerformance?   

  What is the change in entropy of 250 g of qee za,b 4usl o+8fs0ltc;if g:z 7l)1steam at 100$^{\circ}\,C$ when it is condensed to water at 100$^{\circ}\,C$?    $J/K$

  One kilogram of water is l-k ut1 favf1;qmh(g9heated from 0$^{\circ}\,C$ to 100°C. Estimate the change in entropy of the water.    $J/K$

  What is the change inlggkcd 6:e rsu4bw,;do8n( z/, ia:lv 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 sp: f7clto+dgc 6b+ai) xeed 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 kin(c m 2yc2 b5qg2 ieww,nmf8*xtetic energy KE just before striking the ground and coming to rest. What22 qnt*wibmem2cg c x ,5w(f8y is the total change in entropy of the rock plus environment as a result of this collision?

  An aluminum rod condu/5t h4qmp6.:40k ykay icepxgcts $7.50\,cal/s$ 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,nc6ysc/eu 0 ubz-g/k $^{\circ}\,C$ 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 at 3mzb).-v man w80$^{\circ}\,C$ 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 produlg ; i)hn/aif;is-al gho8j3u-vn: d*ces 550 J of worfg;8a ghliuv-nda:j)ii/;loh * 3sn -k per cycle 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 obta:lhk,jszd0l sge 1*zb.pc/t5ining
(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 ordnw 24+jy6c:ztdd wty y9 ;6hnger of increasing probability: (a) four aces and a king; (b) six of hearts, eight of diamonds, queen of clubs, thw z9 nwjct 4y 66t+ndydyg:2h;ree 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 yzdwnwsn-oeg j4z*a2:e1g k *;our hand and drop them on the floor. Construco e2jws- k g4*z*1:zdnewga;n t 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 produce about 40 W of electricity per sq,dy w6kx p:ok-uare meter of surface area if dy ,kp-wo:6xk directly facing 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 (c2 dj72.rxyzj xr +ilduring peak demand by pumping water to a high reservoir when demand is low and then releasing it to drive turbines when needed. Suppose water is pumped to a lake 135 m above the turbines a2xrd7zj(yi. l+c 2xr jt 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 +xr oc*nqcs2: 8 0ygquwo5ln 3by a dam (Fig. 15–27). The water depth is 45 m at the dam, and a steady flow rate oorq8cg n5 y*u32 oqcl0xsw:+nf $35m^3/s$ 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 z4: iqsn-v0(4qe wacbbuilt 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 oqi q 4 b4n-:avc0ewsz(f 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 gasolinet3ma .jk8(ex w engine has an efficiency of 0.25 and delivers 220 J of work per cycle pe (jakw. m83texr cylinder. 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 (the8p1 5nvdiah9 f3u 9jahev;w vt5mvj4, reverse of a Carnot engine) absorbs heat from the freezer co9j1 5ht n,m 5av9epf8v43hv da viw;ujmpartment 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 thmahwzk5v :n;2 at made use of the temperature difference between water at the surface of the ocean and that several hundred meters deep. In the tropics, 5mk nhva;2w:zthe 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 q+r emwc4o/z /h8z(rvl7 i y+j in opposite directions when they collide and are brought to rest. Estimate the change in en7 o8/+y( rlr v4mj/h+z iqcwzetropy of the universe as a result of this collision. Assume $T\,=\,20^{\circ}\,C$    $J/K$

  A 120-g insulated alumitgogd 4z8+mud ;-uck,.m.rj onum 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 perform klo4( i, bgzg5b:)s)vot:kimance of an ideal heat pump that extracts heo k5gi)igbz) lm,s4k: t:( vboat from 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 3x5rer43cyiu w: fg.c uf*z4o in a car 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 loo e wff 3k jk25h m.+qcwods)70jka0;nwer 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 0 h86 amwqhq.oyvnd py/g gd9,zdq-j- x6,0an state A to state C in Fig. 15–28 for each omh0.gj -x0a,zq-gqyp9,d6vo8d hn6a q d n/ywf the following processes: (a) ADC, (b) ABC, and (c) AC directly.

  A 33% efficient power plant puts out 850 MW of electrical power. Coolhq -bei2b fsk4gv -3rwn+; yk(ing towers are used -2;nw4h3 r fkby( keqsg -+bvito take away the exhaust 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 delivers energy at 980 MW using steam turbines. The st2r8x 4c5pimp l7 lqu,team goes into the tu7 5p c8q,uip lxtlm4r2rbines superheated at 625 K and deposits its unused heat 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 opaf568wi+s bv .0rbk 74 qnrypyerates at about 15% efficiency. Assume the engine’s water 7b4y+a 0rbqn.r 68 sy5p kwivftemperature of 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 tall cylindrical jar of cross-sectssh 7z3;qgbye6 .v*w xional 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 resu7-hqg5,j/ i p 0rx/azyu.ub ljlts 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 room;t vf-*-jw2 wzmu*q 9 * tat3aihj/pc ajdz:u/ 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 “refrigerator wf9 az4h9 .qhlkt 0;kltith 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 andf9 th .0qzhk9la;4 ktl 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