What happens to the internal energy of uo*jty . ; dylh.,oau2water vapor in the air that condenses on the outside of a cold glass of water? Is work done or heat exchang..;,o oa dyyt*uuj2l hed? Explain.

Use the conservation of energy to e *d9yb:e7ulcv xplain why the temperature of a gas increases when it is quickly compressed — say, by pve7 b9lu:*cd yushing down on a cylinder — whereas the temperature decreases when the gas expands.

In an isothermal proces kc4h+ay :egye6+x0u5 k4ek ejs, 3700 J of work is done by an ideal gas. Is this enough information to tell how much heat has been added to the systx + augkek4hyy60ee +5:4jk ecem? If so, how much?

Is it possible for the temperature of a system to remainm)(t :r.vtgdg i(j r9u constant even though heat flows into or out of it? If so, give one or two examplesitr( :dgtm.)rug9(vj .

Explain why the temperature of. dmm/y7txh+ :imi ju5.abfr3lpl0.e a gas increases when it is adiabatically compressed+/xi.fmamh:30b5 l j.yu til.pr 7 edm.

Can mechanical energy ever be transformed completely into heat or internal ener * ou,xbfoi ;:91smxpjgy? Can the reverse happen? In each case, if yourpoox m*;, :fji usb91x answer is no, explain why not; if yes, give one or two examples.

Can you warm a kitchen in winterz q9vy cg0)9ns by leaving the oven door open? Can you cool the kitchen on a hot summer day by lzv 0)qnscyg99eaving the refrigerator door open? Explain.

Would a definition of vxlx v)3tkt0 i-6yi+rheat engine efficiency as $e=W/Q_L$ be useful? Explain.

What plays the role of high-temperatur/k5n -(h;fa e7ibj-ub-yh ka se and low-temperature areas in (a) an internal combustion engine, anhb-jb/if;hkek-7s(ay n5a - ud (b) a steam engine?

Which will give the greater i.wkgish rn 5.,, pt:0+tgq:ihrqddz 6mprovement in the efficiency of a Carnot engine, a 10 wtpg0i gr tsr 5h,dd .:.q:n i,+k6hqz$C^{\circ}\,$ increase in the high-temperature reservoir, or a 10 $C^{\circ}\,$ decrease in the low-temperature reservoir? Explain.

The oceans contain a tremendous amo/4ou 06w,+l qry x, 17z2qabfrqgjlvaunt of thermal (internal) energy. Why, in general, is it not poss1wlu, vz,qgxrr46o bjqfa/2 0q yla+7 ible to put this energy to useful work?

A gas is allowed to expand (a) adiabatically and (b) isothermally. In eacp 0m y9xe4me;dh process, does the entropy increase, decrease, or stay the same? Expla04dpy9me m;xe in.

A gas can expand to twice its o-(m1e odhzuoh vor1 lzwv 7322riginal volume either adiabatically or isothermally. Which process would result in a greater change in (ulw1v2 h e rv1dhoz7- o3z2omentropy? Explain.

Give three examples, other than those mentioned in zweyy-* c76s4n5qkv9yy24 utqoav n0:q: ztr this Chapter, of naturally occurring processes inys nk2:yctq z4v y*y ztn407er5wv o:u6aqq9- which order goes to disorder. Discuss the observability of the reverse process.

Which do you think has the greater entropy, 1 kg of solid ir,cs4vejmpumvc8 4p.y 3t-*; pjmb;tq .be0yxon or 1 kg of liquid iron? Wh8*c0 e by-4cvptjm;bsue,3p;jtvm4xp. q.my y?

(a) What happens if you remove the lid of a bottle containinu toa*)vbq 5p-.)fiz rg chlorine gas? (b) Does the reverse procfoi abv)t.q 5zrp-*u )ess ever happen? Why or why not? (c) Can you think of two other examples of irreversibility?

You are asked to test a machine that the inventor calls an “in-room air conditioze()lw3tos 4ht 76x lener”: a big box, standing in the middle of the room, with a cable that plugs into a pow7)( 4z te3txh soewl6ler 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 processes (other than those already mentioned) that woflj+ tlq08h 1guld obey the firsqfl 1lt08+ jght law of thermodynamics, but, if they actually occurred, would violate the second law.

Suppose a lot of papems f)1ka*q4n ars are strewn all over the floor; then you stack them neatly. Does this violate the second lfak)m 1n4sa *qaw of thermodynamics? Explain.

The first law of the(-dt6yv k9huxrmodynamics is sometimes whimsically stated as, “You can’t get something for nothing,” and the second law as, “You can’t even b(6h duky-vt x9reak even.” Explain how these statements could be equivalent to the formal statements.

Entropy is often called “t-8qu an08sr srtzg r+6ime’s arrow” because it tells us in which direction natural processes occur. If a movie were run backward, name some processes that you might see that would tell youstgu q6sa-r8 zrn+0r 8 that time was “running backward.”

Living organisms, as they grow, convert r3 y48 obbi7osrelatively simple food molecules into a compl4bi 3oor8b s7yex structure. Is this a violation of the second law of thermodynamics?

  An ideal gas expands isothermally, perfow-( 9g7f,tq8pkez eix rming $ 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 frictionless piston and maiae+zy2w07d7s/ge ,(ix;s ;cjfl sge fntained at atmospheric pressure. When 1400 kcal of heat is added to the gas, the volum e7s2ejgl wgai0xsd ;+s/ e(zc,7fyf; e 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 at cn0sab tf:(zba2y +(ciw.at 6zonstant pressure until its volume is halved, and then it is allowed to expand isothcsb2:+6tn y(0fiwb azza(t .a ermally back to its original volume. Draw the process on a PV diagram.

Sketch a PV diagram of the following process: 7on9mwkxs0uncld+:i6 zr -w02.0 L of ideal gas at atmospheric pressure are cooled at constant pressure to a volume of 1.0 L, and then expanded isothermally back0woxm0zsc d n6-n 7k9rl:w+u i 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 initially at 4.5 atm of (absolute) pressg;;wdt1tt1j n1 v ,yhllb)c7 pure 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 heph;,7nl t1l;gd 1jy tcvt) w1bating 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 t7f-/)eo wgckq e.uj ,in half slowly, while being kept in a container with rigid walls. In the prooc)k-, f/e qug7 e.jwtcess, 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 adiabaticallyzie j-w(3xga4 nj: b/q to half its volume. In doing so, 1850 J of woe4q zg/ji-w xnj( 3ab:rk 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 from 400 mL 27r9d khi8s:lgqgt fli5 ;qsh45r s0q to 660 mL. Heat then flows out of the gas at constant volume, and the glilq 9h5 :f; sqisq rh725t80 4dkgrspressure 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 adiabv2 a15moop0r7t r38p-h vedm7 azezi. atically, performing 7500 J of work in the process. What is the change in temperature of the gas during this expant p-7p0hv 5mzeazd7v . arm3e1 2ioor8sion?   $ K$

  Consider the following two-step process. Heat is allowed to flow out of an ides+j9it)0 4kqn gw r-wh7 ;dmnval gas at constant volume so that its pressure drops from 2.2 atm to 1.4 atmn-j0vw;n 4ht+wmgqs9)7rdk i . 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 possiblejtv +;x+) 5uzm/h0tmmw qa)g p states of a system containing 1.35 moles of a monatg xu/m0mth)aw5vqj zp+;+m)tomic 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 fgnl*o7zi h1 /xx-y9q drom a to c along the curved path in Fig. 15–24, the work done bl zq719ih*y/ xon-gxdy 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 stuo:wx /0sb2q cate c along the curved path shown in Fig. 15–24, 80 J of heat leaves the system and 55 J of work is done on the systc bw/so:2qux 0em.
(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 *kz; e -mlmdh*lw+u c3pu +;hfof Example 15–8 transform if instead of working 11.0 h she took a no +m wue u3*pz+ll *khm;fh-cd;ontime break and ran for 1.0 h?    $ \times10^{ 7}J$

  Calculate the average metabolic rate of a person who sleeps 8.0 0q)ctu.a,1.jh u+ jruyqqye* h, sits at a desk 8.0 h, engages in light activity 4.0 h, watches television 2.0 h, plays tennis 1.5 h, and runsj,q ra*q0qeutu.y. uj1yh+)c 0.5 h daily.    $W$

  A person decides to lose weight by sleeping one hour less per f3iduqopp: fme37h. q.f4 ol:day, using the time for light activity. How much weight ppoe . d: omu:fq37qfli4h.f 3(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 performing 3g-vepxb+0ha y*t m -r5200 J of useful work. What is the efficiency of this engi 0pg*5yea tb-v mh-rx+ne?    %

  A heat engine does 9200 Jz n5*anrpu1 mf(c*6kg j3o3tr of work per cycle while absorbing 22.0 kcal of heat from a high-(a1mtr kjo 3c*n5fg z*36runptemperature reservoir. What is the efficiency of this engine?    %

  What is the maximum efficiency of a heat engine whose operating tempera nqwg3j4sxv +o kkx 3y1fv;8v-tures are 54f x;nxv-k k+vq8g33s yj1wov80$^{\circ}\,C$ and 380$^{\circ}\,C$?   %

  The exhaust temperature of a*+q5u) uh ewae heat 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 maximum theoretical (Carnot) 5xykx)a6j)ykvn + hx1t) 2w2 najhup) efficiency yx5u)taykh 2 xjnjhv n)p6+1w2) ka)xbetween 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 than ha;rw q,t)d ,r rlu/s;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) tort sahqd,w ,u;;/lrr) the liquid nitrogen “fuel” (Fig. 15–25)?    %(Round to the nearest integer)

  A Carnot engine performs work at the rate of 44pkj02h .dtl c)3jfy i p1g.at10 kW while using 680 kcal of heat per second. If the temperature of the heat sourc.0ijta )3c1y.lhp1t2fj dkgpe is 570$^{\circ}\,C$, at what temperature is the waste heat exhausted?    $^{\circ}\,C$

  A Carnot engine’s operating temperatures wgc 4.(8 4g7drhd,ek xz,xuzj 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 hp+ qabnv 1aj 3ywjvf*(9z 6jl:eat discharged per second, assuming that the plab 9 y1nwzv*l :63(fjqvjpj+a ant has an efficiency of 38%.    $MW$

  A heat engine utilizes a heat orau7 qacl12, 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 exhausemmor0g g)h2rp79 *bfts its 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(i(r xdy7cs2kf -u;wk being the approximate heat input of the second. The operatid risxcu (k;7k2f-(w yng 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 coil is - p+fc6e 9v 6g0wmhje,j15$^{\circ}\,C$ and the discharge temperature is 30$^{\circ}\,C$. What is the maximum theoretical coefficient of performance?   

  An ideal refrigerator-freezer operates t9je4pt 8kn:jw/rbe 0 *th *bfwith a in a 24$^{\circ}\,C$ room. What is the temperature inside the freezer?    $K$

  A restaurant refrigerator has a coefficient of perfor4jimw bz6 wlt w77+g p((qibi9mance of 5.0. If the temperature in the kitchen outside the refrigerator ib mw6lti7 i+(i4 gw9zq(j 7bwps 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 keexj te 429/llm u9jlw*zp 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 ow/f3h/o9o2k2lmdca mg hm9 2 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 possibr i:oxjzbhh(il7/o .,le to run it backward as a heat pump, what would be it,h i o:i/h7rbojlzx.( s coefficient of performance?   

  What is the change in eug fwp6z.a3x5 49edou ntropy 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 ru/sa2usyz5) d/3a c sheated from 0$^{\circ}\,C$ to 100°C. Estimate the change in entropy of the water.    $J/K$

  What is the change is p3ot gfjk f1.v9,9avn 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 initiab7 *t s.x;bgzt a/*exql speed 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 Khg xt2fzs e,7d+tffw el104/kE just before striking the ground and coming to rest. What is the total change in entropy of the rock plus environmentt4fehe x fdw,z gft/+2kls170 as a result of this collision?

  An aluminum rod conducts -y ik mdgk:f)9gs9fv1$7.50\,cal/s$ 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;ruyh yykpatfj*+)bh :;i d:j9,d0fl$^{\circ}\,C$ 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 alumib: tp1v4 +jw jmyc *efxv:e*.unum 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 9i3: )lz qpi y8zyf+)hzkbn:d 870 K and 650 K produces 550 J of work per cycle for a heat input of 2200 J. d+ 88 ykin bph):z)fyli3q: zz
(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, xc t;itbzg dz9e ):s:zr89v,o of obtaining
(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) foxa +(e*2ketu)nx de.dc. /rvpur aces and a king; (b) six of hearts, eight of diamonds, queen of clubs, three of ee( 2* enxdkvput./cd a)r.x+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 drop u9n(*tya. s ny1njke k852qfpthem on the floo( . k*ks9ny ep 8nyu1tnq5fja2r. Construct 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. 15–2kqti hr+6h lu85r:;rf6) can produce 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 of a house thlr 5ri6qhft:h ;8u +rkat 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 6ti1b/2c -fw ujgzsb o8gjv:)pumping water to a high reservoir when demand is low and then releasing it to dri w)1z6obcg-/ibj2u s:jf vtg8ve 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 (2.zigj:4tuk:vf ws-b Fig. 15–27). The water depth is 45 m at the dam, and a steady flow rat- bftkw.:z4u s :ij2vge 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 p.dddmld9ot,)3 uwe+ 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 d ,l+ud e )mwod9.d3ptenergy 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 efficiency of 0.25 and delivers 220 J of(xucx(0u hq 7k /oj/fs work per cycle per cylx(suu (ojq7c/ hx0 /kfinder. 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” refrigeratorky czg6s 7mhs (p/e1c8 (the reverse of a Carnot engine) absorbs heat from the freezer compartment at a tempera1 zgcemsk s( /ph67yc8ture 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 ) .bdvs3 j(bh,ab5uqcx3t kn*be developed that made use of the temperature differsut(3 )bha 3qxv bd.,jb*c n5kence 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 direct:oj42/xd 3s9rg r n((ldswuklgkpo-8ions when they collide and are brought to rest. Estimate the char:nd (9gp( /jw kx8kso2lg do 4-lrs3unge in entropy of the universe as a result of this collision. Assume $T\,=\,20^{\circ}\,C$    $J/K$

  A 120-g insulated aluminum cu;p0 ghl( lxtl*p 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 /r:llw0gc 2 lethat extracts hl:gcwl rl 2e0/eat 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 in a car releases abou,xln9 (w vz9m hhe2y k.t0xdm.t $ 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 lower operating tecbrt,syc0lg2e77 rko fmq 59+mperature $T_L\,=\,20^{\circ}\,C$ 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 ss p -hn6t77 gt*bfc5vbtate C in Fig. 15–28 for each of the following p 67hbsg fn-ptt7b*c5 vrocesses: (a) ADC, (b) ABC, and (c) AC directly.

  A 33% efficient power plant pu11c2;if m(noihr nb t8ts out 850 MW of electrical power. Cooling towers are used to take away the exhaust heat. fr2in; 8b tn ohi(1c1m
(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 steam ylu k x+s/n :u1yzc)16w6rg7vr xsh 8pgoes into the turbines superheated at 625 K and deuk768n s)zr/xcr1 +ygvxu61s:lw ph yposits 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 thedjs1kra0, n,u-v8operates at about 15% efficiency. Assume the engine’s water temper,1s , v-hnjaeut r0k8dature 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 crrrye ,s).8i r/ahk*pm3 coxffi2 9 b7noss-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 okyu 1i/cd t1)xf fat 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 temperature inside a rqj6dp zvbu7mez erk37,, um2 ;rmp +7poom 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 “refrig,huu;e-mw me4 ) e1lwgerator 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 o-14umm eu; hwg)ew,elf 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 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