What happens to the internal energy of water vapor in the air that condenses jf0o*gxm.goc z4p *y*on the outside of a cold glass o.yjfcm*ozg4g** p ox 0f water? Is work done or heat exchanged? Explain.

Use the conservation of energy to explain why the temp r5. 5jt*hbem69le xrd8ddb-jerature of a gas increases when it is quickly compressed — say, by pushing down on a cylinder — whereas the temperature dec.l5jrt 9rddxh6eembb8 5*jd- reases when the gas expands.

In an isothermal process, 3700 J ofp kq0;c+ 3vt);v5*njsajmh a f work is done by an ideal gas. Is this enough information to tell how much heat has been ac5vhj3 0qnav;task)pm*;f j+ dded to the system? If so, how much?

Is it possible for the temperature of a sy .c:aevbii+)e oe: q0wstem to remain constant even though heat flows into or out of it? If so, give one or two e+ei eowa 0 :.viceb)q:xamples.

Explain why the temperature of a gas u9 n/m,p-dce iincreases when it is adiabatically compressem /ep d,n-9iucd.

Can mechanical energy ever be transfod9 v +e*4zrstx 61mpnirmed completely into heat or internal energy? Can the reverse happepimz*e41vr +ds9n 6 xtn? In each case, if your answer is no, explain why not; if yes, give one or two examples.

Can you warm a kitchen in winter by leaving the oven door open? Can you cool r6807uth ugw)2kj(7m h+ 6o wxiqzpjv2ggri9 the kitchen on a hot summer day by leaving the refrigerator door open? Ew(8+2p 7jiu0gz o ru2kqjv9gmi) hgrx6t76hwxplain.

Would a definition of heat . ka d-np)b*wi0*jzizengine efficiency as $e=W/Q_L$ be useful? Explain.

What plays the role of hiltx0lvk chp;l*r nl50n (kc0 8alq52y gh-temperature and low-temperature areas in (a) an internal combustion engine, and (b) vk n05nrc5lqly kh8p*;l0xll( c 0a2ta steam engine?

Which will give the greaterw sebzakf b)/a xeyq.+s(ur/9x) e(h f 1cdm2: improvement in the efficiency of a Carnot engine, a 10 w9 + s)qce(me afx(f.dak :s/ybu)r1zx2 hb/ e$C^{\circ}\,$ 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 thermal (internal) energy. Why, ye/ylqce uxhu2,y)+6 in general, e )6u2yey x/cl+, quhyis it not possible to put this energy to useful work?

A gas is allowed to expand ( * *jmvh-*q/xy;b; 2.1f6botq l z(pkaav hqrya) adiabatically and (b) isothermally. In each process, doh/hakl6vqq* txzm y v-*(;.2; bj 1qyaofbp* res the entropy increase, decrease, or stay the same? Explain.

A gas can expand to twice its original volume eit/xnq4.vu; kwiy )tx1 kher adiabatically or isothermally. Which process would result in a greater change in ekw)vu; n4q 1x /kxy.tintropy? Explain.

Give three examples, other than those mentioned in this Chapter, of natic7bdgq0e78jzg 8ks;d3r 9s)mfod+durally occurring processes in which order goes to disorder. Discuss the observabqg)d ;db szk73e rjm+gi f 9oc0sdd788ility of the reverse process.

Which do you think has the greater ene qf e8yt2i84shyrw9*tropy, 1 kg of solid iron or 1 kg of liquid iron? 89y2 qify8s4tre eh*w Why?

(a) What happens if you remove the lid of a bottle containing chlorineq s, ,zlo3r3kh gas? (b) Does th sor3,hq3,kzle reverse process 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 a-jn6t + 7 *hrsjd6si(vxn2espn “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 switched on, you feel a stream of cold air coming out of it. How d*e jpnrv 7 2tssij(nhd-6xs +6o you know that this machine cannot cool the room?

Think up several processes (other than those already(ka4 xzupng88 mentioned) that would obey the first law of thermody4(gu kzaxn p88namics, but, if they actually occurred, would violate the second law.

Suppose a lot of papers are strewn all over the floor; then you sta5,6wdcte* 5/ij a1c mck 3xi08-xvmn-mb pxywck them neatly. Docdi6 m n , ec-xcx*15mia tp/3x05wymjwv-bk8es this violate the second law of thermodynamics? Explain.

The first law of thermodynamics is som0ae- a t(vsaa0rf6 ry/etimes 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 b/ay0(6-rvarfaa t e0se equivalent to the formal statements.

Entropy is often called “time’s arrow” because it tells us in whicu jq-p*b,te3lh direction natural processes occur. If a movie were run backward, name some processes that you might see that would tell you that time wpq u*elb ,-t3jas “running backward.”

Living organisms, as they grow, convert relatively simple food 0rf avgz )kuv99c95 e(lzk0cfmolecules into a complex structure. Is this a violation of the second law of t zz cfv 5a0kl0)k9evr9u9cg(fhermodynamics?

  An ideal gas expands isothermally, pe kj;xp,g6/4osxc t*urrforming $ 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 mai(/4 a6vfxgolwz;x )gy ntained at atmospheric pressure. When 1400 kcal of heat is added to the gas, the volume is observed to increlg;6(y/ owv)zx4fxag ase 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 volume is halvo1uu6g1owt o7tq27l8zkl p5 qed, and then it is allowed to expand isothermally back to its original volume. Draw the proce1w lkq7go u86tpzout2q51 o7 lss on a PV diagram.

Sketch a PV diagram of the following process: 2.0 L of i-:frbg cc (pf.deal gas at atmospheric rff.b:-g c(pcpressure 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 pressure is reached.

A 1.0-L volume of air initiallyp::o k/r8z qjn 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 heatingnzjp:r8/: q ok 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, while belcd;6jo/ e ir(:u.a*a*xxisr(; z e lming kept in a container with rigid walls. In the process, 265 kJ of heat left the gas.:x*is e*i/ .raa m; xl;j(l(dreouzc6
(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 adiabaticallg 9)fgis.hlu.,.kn ev d81icdy to half its volume. Ini d.c.8)dv eif9 g.,k1ughsnl doing 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 pressure of 3.0 atm from 400 mL to 613rinsnc x6,tunmb d 1d)-j f-60 mL. Heat then flows out of the gas at constant volume, and the pressure and temperature are allowed x , )-1nnsfr63nct1 jdmbiud- 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 idea(nfvu7kz xk1xz7i jr( 9f+e hrxf g+.cx4o.,o l monatomic gas expand adiabatically, performing 7500 J of work in the process. What is the change in temperature ox + zougz,v(.xc1 k9hi k+.xf r7ro(nffjex47 f the gas during this expansion?   $ K$

  Consider the following two-step process. He ph nv2k*in)k9at is allowed to flow out of an ideal gas at constant volume so that its pressure drops fromn v2 k*i)h9pkn 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 possibf4q ; .qso9q t(d8a/vwowu2m ble states of a system containing 1.b; svw4mo(u dq8 wf2aqqt/ 9o.35 moles 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 pbav+vb3 9y* dadz3oty0; 6qgcurved path in Fig. 15–24, the work done by thapdb3dzo y6v *0;a+ty g3q9vb e 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 sup c/yzpap1ohn16 c * wax0egts j.2-9tate c along the curved path shown in Fig. 15–24, 80 J of heat le26gpn. 1-y9w eah*u oat/sz0 c1p cpjxaves 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 xfeuzmo8 tnnq/* 5 0w.working 11uf z.0 8e5mnx*onq/w t.0 h she took a noontime break and ran for 1.0 h?    $ \times10^{ 7}J$

  Calculate the average metabolic rate of a person who sleeps 8.0pm5np 8 k8hdu1sa+wu6i 2+bng ) wz 9c2tvi*bk h, sits at a desk 8.0 h, engages in light activity 4.0 h, watchei6 ktwzkb9*5 d2 1min8ws)82a+ +pvnbcuu gphs television 2.0 h, plays tennis 1.5 h, and runs 0.5 h daily.    $W$

  A person decides to losew1f l+iaj )e,brislz1ud -+.i weight by sleeping one hour less per day, using the time for light 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 jw-lfi,u.+i1es zbr aidl 1+) 40,000 kJ of energy.   kg(retain one decimal places)    $lbs$

  A heat engine exhausts 8200 J of heat while performing 3200 J of useful workd-s7kah7-p.5yj fg9x x1d8.kbqm gol . What is the efficiency of this enginxmha1dgp8q kkl.d7f9 o - b-jyx. 7sg5e?    %

  A heat engine does 9200 J of work per cycle while absorbing 20c m *pci/esu-k rbo:;2.0 kcal of heat from a high-tb 0o r/ -:skm;u*cicpeemperature reservoir. What is the efficiency of this engine?    %

  What is the maximum efficiency of a heat engine whose fh9z1 vhcev6;operating temperatures are 6hz c9v;ev1hf 580$^{\circ}\,C$ and 380$^{\circ}\,C$?   %

  The exhaust temperaturv;uziuat 61a8e of a 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),0f)i biq (hu9 ;3cd6 0v-qxnedzvuja efficiency between tempb0 aqi(vhdfe9qx,uz- v)jndi; 63u0 ceratures 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 hea uau6t3*:w lsvt engine’s hot environment be hotter than ambient temperature. Liquid nitrogen (77 K) is about as cheap as bottled water. What would be the efficiency of sa tl3vuu*6w: 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 thed5 ts rbs4ve99 rate of 440 kW while using 680 kcal of heat per se95dbtsv4 r9second. 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 operating temperatures are 28:(2wx ny wcc*( ridpr10$^{\circ}\,C$ 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 heatywdxv*s: c: fr /vc1h7 discharged per second, assuming that the plant has an efficiency of 38yvwc:17 srh*x:dcfv /%.    $MW$

  A heat engine utilizes a heat,il ,ibco;)(ewgh jct m511vh 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 7b1:dunfq7+.g2h (by)mm zlpkbqa(tits 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 on9. )riji- tsa r:c7ceutput of heat from one being the approximate heat input of the second. The operating temperatures of the first are-7ecarr s)i9 jt.c:in 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 k gbb 3(,6ukj:+m/rwtgjozc7 jp0/ra 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-fc/(kv 5c)upap reezer operates with a in a 24$^{\circ}\,C$ room. What is the temperature inside the freezer?    $K$

  A restaurant refrigerator has a coem4dp/vl1a+/ lm 1mmfj fficient of performance of 5.0. If the temperature in the kitchen outside the refrigerator i/vm j lp/mml1af1dm4+ s 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 sdm5tgghk/* 1hb/; uay:up0p 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 ayupis ll2ut3l1 l/x042 ahbs-t 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 run it8 mghis0 );bixm 0/gvt backward as a heat pumpvx;b0mg ths mg)i0/ i8, what would be its coefficient of performance?   

  What is the change in entropy of 250 g o6iumcqm4tu . .f steam at 100$^{\circ}\,C$ when it is condensed to water at 100$^{\circ}\,C$?    $J/K$

  One kilogram of water is heauv1w9rvf8i .dted from 0$^{\circ}\,C$ to 100°C. Estimate the change in entropy of the water.    $J/K$

  What is the change in entropy ofycu, ;a( f,+cu-wy gih $1\,m^3$ 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 initib/w(,pnl hb 9n :pih.zxt1fs.al 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 KEm bka . 7*lbg9aqp19rn just before striking the ground and coming to rest. What is the total change in entropy of the rock plus environmen7amnql9 agrbk9b*. p1t as a result of this collision?

  An aluminum rod conductmln5-.1zw xby d gt)( ,(ikive-3u1o svkuff- s $7.50\,cal/s$ 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 3o 4ymfxz)hw(( 0$^{\circ}\,C$ 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 alut f 3hujt5+/q+miao.hu yxi50minum 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 9emqw:cr 7e7mw2rk:lK and 650 K produces 550 J of work per cycle for a heat rwm7m q::l2ew97rec k 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 th)+ msb kmh(922tgpnam row two dice, 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 increasfxmi9m 5e.7ob ing probability: (a) four aces and a king; (b) six of hearts, eight of diamonds, queen of clubs, three of hearts, jack of spades; (c) two jacks, two queens, and an ace; and (d) any hand having no two equal-value cards. Discuss.m 9imfeoxb75 your ranking in terms of microstates and macrostates.

  Suppose that you repeatedly sa3 be0eer s 1k:f0iq8 a .kuk1gf2ji7lhake six coins in your hand and drop them on the floor. Construct uffere.gi1ke sl28aak:i 0k 130q 7jba 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 square meter+ : u4)viebqye2oi .nb7zx7vf of surface area if directly facing the Sun. How large an area is required to supplyfeb evb 2+)x:quo7ziy7 vin.4 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 water to aeq2us7*nc:u(m , mjbi high reservoir when demand is low and then releasing it to drive turbines when needed. Suppose water is pumped *(b e,nsu 2ji mcqu:7mto 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 9oyp1kh; (uaz7p d;w:at cwt 1depta 7hzkwo pu:t 9;da;w1cpy1 (th is 45 m at the 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 MW dvjd-hijh niltm b*w* g33080of usable work while taking in 3.00 MW of thermal energy am8j-h 0tw nvjg ihi 3db03**ldt 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 enga b2g-b05 dgtrine has an efficiency of 0.25 and delivers 220 J of work per cycle per cylin2 bggb5td0r a-der. 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 reverse of a Carnot engine) absorbs heat fr / v*bcexg*b*rom the freezer xb ge***r/bvc compartment 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 nzcoh f1 1vf8z,(q fm6ywr5oet: p,0trk43meuse of the temperature difference between water at the surface of the oceat0p(8zym3r:6 oecq fmf4rfvek n1, t5,ow1hzn 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 direc, ,92tp gmhqc-og rk6bcc9mj4tions when they collide and are brought to rest. Estimate the change in entropy of the universe as a result of this co6 t9m p9ckgjc4hgq,-m ,orc2bllision. Assume $T\,=\,20^{\circ}\,C$    $J/K$

  A 120-g insulated aluminum cup at(2rxdgy.(wj f 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 ixt, jit n2-voj-8go cf(z3 s(that extracts heat fromo,3-s(zgvfioi (c8jjt nt-x2 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 aboutezdv 5l0s.)cidc r;7q $ 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 temperature g4e yza/*m. (lokm(ja$T_L\,=\,20^{\circ}\,C$ 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 goinz)b jsx3/dz -cg from state A to state C in Fig. 15–28 for each of the following processes: (a) ADC, (b) ABs3z/zcd b)xj-C, and (c) AC directly.

  A 33% efficient power plant puts out 850 MW of electrical power. Cooling tow ;ft)6z -q**qlwtr tx hbj.ev-ers are use bjztq*6qftl-vtx ;r)*eh.-w d to 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 eh v z1,r k6a;j/ujz2asnergy at 980 MW using steam turbines. The steam goes into the turbines superheated at 625 K and deposits its unused heat in river water at 285 K. Assume that thej rk1za ;as6 h2ujv/z, 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 jee sq8dm;q0x*ekvs3c+apa(,e y)g0% efficiency. Assume the engine’s water temperature sce*qqak , 8ep+vgj(a0dxyse3 0 ;)e mof 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 cylindrihqjfttq07n 5*)ju(d-j jnn;5n x, zzjcal 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 resb xa4u)v3 0e ls2.yvdm ,n glr41eajs,ults 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 keepsrcpzt 0 +xh5pcnx 3. qpbw,76q the temperature 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 “refrigerator with an open door.”8p 1uj595+kowo erpsi /xu.tz 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 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 rowktriu8o 5z+uespo 5jxp9/ 1.om 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