What happens to the internal gmyl-sg tsm-w:, ;+k penergy of water vapor in the air that condenses on the outside of a co ksp:-gmtl, -;sg w+ymld glass of water? Is work done or heat exchanged? Explain.

Use the conservation of energy to explain why the temperature of a gas increafynw26pt 8)so ap,g v,ses when it is quickly compressed — say, by pushing down on a cylinder — whereas the temperature decreases when the ga2fvwpa8,s nt ,o)gpy 6s expands.

In an isothermal process, 3700 J of work is donesk b-6is)/q)j7ue kl8qt7ihaym+fx 9 by an ideal gas. Is this enough inf-7ih7)se 6+jxstq m)fbyiq8k9 aulk /ormation to tell how much heat has been added to the system? If so, how much?

Is it possible for the temperature of a system to rem)a1 jsy25s8afib.j/ /za hf+qqr o* mjain constant even though heat flows into or out of it? If so, give one or two ex r5af 8o 1 jz.h)ysajfa qi/+qs/bjm*2amples.

Explain why the temperature of a gas increases when it is adiabatically hbrw pape5;i of,;*.qcv ch+ +compressed.o5+ w haq+;,icp*bhev;rfc p.

Can mechanical energy ever be transformed completely into h uxy.8w/mq8 sm:wur*kly+;:tqm, aa9ljp * kf eat or internal energy? Can the reverse haul jakwfqq*rx 9tp wuy ma;8.,ly/m *+km8: :sppen? 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 k b1m)lzt dx;0kc16td? Can you cool the kitchen on a hot summer day by leaving the refrigerator door open?0zmc1x;1)tk6kdb tl d Explain.

Would a definition of heat engine efficienc/tinbtxi /v2a8f 4mri*gk -/jy as $e=W/Q_L$ be useful? Explain.

What plays the role of high-temperature gu -m98(k bs+bty 6lzvand low-temperature areas in (a) an internalbg (ky 6m+l8zu- btsv9 combustion engine, and (b) a steam engine?

Which will give the gfnx-q088*bp.dgpb gdaws. c :spn*s.reater improvement in the efficiency of a Carnot engine, a 10p .dcw.. 8d-bbn:** xpsqsnag08fs pg $C^{\circ}\,$ 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 thermaidam )p* ;pf4m p0k1 s6o6ncvil (internal) energy. Why, in general, is it not possible to put thisamkm6dpc ovp1f i i406 ns);*p energy to useful work?

A gas is allowed to expand (a) ad xqbfzjsyvb85/-u i( (ykqy/:iabatically and (b) isothermally. In each process, does the entropy inciuy5 :(z kjqs/8b-q yvyx/(fbrease, decrease, or stay the same? Explain.

A gas can expand to twice its original volume either adi k4n2,k gavyo9abatically or isothermally. Which process would ro2kgkn,4yv 9 aesult in a greater change in entropy? Explain.

Give three examples, other than those mentioned in th0h1i m8t xl9 .+b 3sveuct3hnhis Chapter, of naturally occurring process98x tchse+ .3uihvbm n0t3h1les in which order goes to disorder. Discuss the observability of the reverse process.

Which do you think has the greater entrop)xl(w1nau: jsy, 1 kg of solid iron or 1 kg of liquid iron? Whyu1) lw nxja(s:?

(a) What happens if you remove the0fqdm*qes- 3 n/k,ra g lid of a bottle containing chlorine gas? (b) Does the reverse process ever happen? Why or why not? (c) Can you think of two other examples of irre 0s/,n3geq-fmk dqr a*versibility?

You are asked to test a machine that the inventor calls an “in-room air cogv.ksl w7w2m4nditioner”: 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 do you know that4vswk 2 .w7gml this machine cannot cool the room?

Think up several processes (other than those already mentioned) thaky4s1.ysx8:xw c w uo.t would obey the firsxw8:k.yo w4cys1s.u xt law of thermodynamics, but, if they actually occurred, would violate the second law.

Suppose a lot of papers are strewn all over the floor; then z:uybpy*i69h+vl6. 7n kdbzq you stack them neatly. Does this violate the secon9 nbpklyiz6 b.z +v6dh*uq:7y d law of thermodynamics? Explain.

The first law of thermodynamics is sometimes whimsically st .5 0ilw0tnc8pp9ic/s7r nqzuated as, “You can’t get something for nothing,” and the second law as, “Yi 09pstcn5z 0 upin clq/.7wr8ou can’t even break even.” Explain how these statements could be equivalent to the formal statements.

Entropy is often called “time’s arrow” because it tells us in which directf+zvbdjw4/ )lb:icr 5 ion natural processes occur. If a movie were run backward, name some processes that you might see that would tell you that time was “running backward.vi4br+cd5 w: f zb/l)j”

Living organisms, as they grow, convert relatively si+ lag p21vabe)mple food molecules into a complex structure. Is this a violation of the second law of tg+2) av1blp aehermodynamics?

  An ideal gas expands isotherzg,c (jqy7vb 0mally, performing $ 3.40\times10^{ 3}J$ of work in the process. Calculate
(a) the change in internal energy of the gas,
(b) the heat absorbed during this expansion.    $J$

  A gas is enclosed in a cylwjry8y 2qi8 8dinder fitted with a light frictionless piston and maintained at atmospheric pressure. When 1400 qyiy 882rwdj8kcal of heat is added to the gas, the volume is observed to increase slowly from $12m^3$ to $18.2m^3$ Calculate
(a) the work done by the gas .   $ \times10^{5 }$
(b) the change in internal energy of the gas.    $ \times10^{ 6}$

One liter of air is cooled at co,dp4nz;v i4 m/zkcq7j( da7kt-s2nthnstant pressure until its volume is halved, and then it is2;74sk/mj dkz nctd(7i,tpv 4 qaznh- allowed to expand isothermally back to its original volume. Draw the process on a PV diagram.

Sketch a PV diagram of the following process: 2.0 L of ideal g4 wy. cc3w8ye4fe(hcwas at atmospheric pressure are cooled at constant pressure to a volume of 1.0 L, and then expanded isothermally back to 2.0 L, whereupon the pressure( he.cy4 w8c4fyw ec3w 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) pressure is all9w)tkhy hq 9c,owed to expand isothermally until the pressure is 1.kh 9)h qytw9,c0 atm. It is then compressed at constant pressure to its initial volume, and lastly is brought back to its original pressure by heating at constant volume. Draw the process on a PV diagram, including numbers and labels for the axes.

  The pressure in an ideal gas is cut in half slowly, while being kept in a contai.)qw5 8xkn*vr;e j sganer with rigidj*ngw5 s.;)v rqak8ex 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 adiabaticalv -h8 sl)r-jtply to half its volume. In doing so, 1850 J of work is done on the gas. h-pv )-tjl8sr
(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 fc s 37r3 oq3a4ebxys+atm from 400 mL to 660 mL. Heat then flows out of the gas at constant volume, and the pressure and temperature are allowed t7yqe43+sroc 3sbxfa 3o drop until the temperature reaches its original value. Calculate
(a) the total work done by the gas in the process,   $J$
(b) the total heat flow into the gas.    $J$

  One and one-half moles of an ideal monatomic gas expand adiabatically, perfor81wb i2qwls+jming 7500 J of work in the process. What is the change in temperature of the2b8wwj+is 1 lq gas during this expansion?   $ K$

  Consider the following two-step process. Heat is allowed to flow out of an ideaem( pxxcm) s-/l 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, ) /-(psxmxemc where the temperature reaches its original value. See Fig. 15–22. Calculate
(a) the total work done by the gas in the process,    $J$
(b) the change in internal energy of the gas in the process,    $J$
(c) the total heat flow into or out of the gas.    $J$  ----待选择----intoout  the gas

  The PV diagram in Fig. 15–23 shows two possible states of a system containin2oq: omt vp:5mg 1.35 moles of a monoqp :v2m:5omt atomic 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 curu p (juvs6k7pdscgd85 17hg3s ved path in Fig. 15–24, the work done by the316ssj gk p7u5dcs7(pgd hu8v 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 curved p;f hiih+/6wz krw mhj /-1vez*ath shown in Fig. 15–24, 80 J of heat leaves the system and 55 J of work is done on th1ijkzme zr hw6//ihfw; -hv+*e 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 insteadkk0-v9f imds2*jp6 g j of working 11.0 h she took-d0k jmgk v96*i 2fspj a noontime break and ran for 1.0 h?    $ \times10^{ 7}J$

  Calculate the average metabolic dw tamd3p az8vd(h( 6.xk:y51n)wet orate of a person who sleeps 8.0 h, sits at a desk 8.0 n3dxm() 1d awt hz (6.vowad8:ke 5ytph, engages in light activity 4.0 h, watches television 2.0 h, plays tennis 1.5 h, and runs 0.5 h daily.    $W$

  A person decides to lose weight by sleeping one holtl/gu e 9vs ,h (pw4qk)qdbm7nu5m)(ur 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 intaeuu g9 /k5(dq m4lw thns,bl7 (p))mqvke? 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 whi/7 :j-4x pnlop z4tkctle performing 3200 J of useful work. What is the effipt4 j 7-xckoptl /4:znciency of this engine?    %

  A heat engine does 9200kp ip) 7r +heel4cm3n- hsm4a0 J of work per cycle while absorbing 22.0 kcal of heat from a high-temperature reservoir. What is the efficiency of this engine?4rl4ain)e0m7ppmsh khc 3 -+e    %

  What is the maximum efficiency of a heat en08nra9u zc;l gdv )po:6xtx4ogine whose operating temperatures are 58rx0zol)odcg98a n x v46;:upt0$^{\circ}\,C$ and 380$^{\circ}\,C$?   %

  The exhaust temperature of a heat engine is 230c.upuyp9k- * w t(w(of$^{\circ}\,C$. 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 maxi.gkuv,io /;jmmum theoretical (Carnot) efficiency between temperatures o/j.iuv,gok; m f 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 e( hvf9:o,htpn ngine’s hot environment be hotter than ambient temperature. Liquid nitrogen (77 K) is about as cheap ahn(t pf v,9:ohs bottled water. What would be the efficiency of an engine that made use of heat transferred from air at room temperature (293 K) to the liquid nitrogen “fuel” (Fig. 15–25)?    %(Round to the nearest integer)

  A Carnot engine performs work at the rate of 440 kWl +tlo(+t/ zfy while using 680 kcal of heat per second. If the temperature of the heat source is 5ztl +l+f(oty/70$^{\circ}\,C$, at what temperature is the waste heat exhausted?    $^{\circ}\,C$

  A Carnot engine’s operating tempera4kky77- dxc lutures 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 pujn(h py2 8rg+vts out 550 MW of electric power. Estimate the heat discharged per second, assuming that the plant has an e h8rv2j+y( gnpfficiency of 38%.    $MW$

  A heat engine utilizex9 kmwx*uebx. 6wz3-fs 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 ublj 2k vfd),zte1b:e jg-6j 5heat 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 enginglfkl1)lu2 duc1 )5xq i;8,g -*u lkh/amoifies work in pairs, the output of heat from one being the approximate heat input of tl-g ii/i5 m,c2f)l1 1 uk8xqg*h )aklu;fuodlhe 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 con5c0in yl;05mmuo exyv m1t8b m;hx-4il is -15$^{\circ}\,C$ and the discharge temperature is 30$^{\circ}\,C$. What is the maximum theoretical coefficient of performance?   

  An ideal refrigerator-ftvm x5-s2 ckj5k7kaw 8reezer operates with a in a 24$^{\circ}\,C$ room. What is the temperature inside the freezer?    $K$

  A restaurant refrigerator has a coefficient of perfojnm:b*bva)snf+16 sf1km r0 drmance of 5.0. If the temperature in the kitchen outside the refriger s+1b m d1jfrvfsabm:6n0* )nkator 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 tlnj 9rm:-o:mdo20 rv+loea0k/po n j;zce; ,vo keep 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 atp57v :nlr 9scec pp9b) 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 rujyd l,v z7g((kn it backward as a heat pump, what would be its coefficient of pel ,z(yvd7jg(krformance?   

  What is the change in entropy+ uop k;jz w9hpm lq1,9mo0ir/ 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 wf(u* *9tqi/fawr2qyy 4 2cyt is heated from 0$^{\circ}\,C$ to 100°C. Estimate the change in entropy of the water.    $J/K$

  What is the change in entropy of d9fn lzt/o ) gu(,+hjv$1\,m^3$ 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 te5v9(unaoxj (3lpy*/t) /x 7t n cqrclt.e:aspeed 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 strikinm nkf:u61pqv:kbw i12miee0/77lnwx g the ground and coming :xnfi72ev6 0q1k/ nmliwbu1pm e7wk :to rest. What is the total change in entropy of the rock plus environment as a result of this collision?

  An aluminum rod conducts g/+o57i zpq xdl+ndx 6$7.50\,cal/s$ 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 3qh4hby0 qt rcr4,z;g ,zr),j t0$^{\circ}\,C$ 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 alummf (hh uq ol6eu9nh2*tm3 vl9,inum 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 6/)8amkyl0v1 0muwv -d uy2 ewi50 K produces 550 J of work per cycle for a heat input of 2200 J. u 2avk1-0i0 yel mwvym8 /uw)d
(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, o u)ye9ytnor5 :f 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 increas+ btaas q2(m+ring 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 your ranking in terms of mica+r2+ q( bsamtrostates and macrostates.

  Suppose that you repeatedly shake six coins in your hand andhw/5)w0/sksc j,eto)gwazvn b;/hue5b 3 d ,d drop them on the floor. Construct a table showing the number of microstates that correspond to each macrostate. What is the probability of obtaini/)dtjcs ,3) hkadu5hewbwv0/b /sw;n,g eoz 5 ng
(a) three heads and three tails,   /64
(b) six heads?   /64

  Solar cells (Fig. 15–26) can producuvo:o w1*rzhpd3b yg)e: p,/he about 40 W of electricity per square meter of surface area if directly facing the Sun. o1yohub ,h:w3pz*/d v :pre)g How large an area is required to supply the needs of a house that requires $22k\,Wh/day$ Would this fit on the roof of an average house? (Assume the Sun shines about $9h/day$)   $m^2$

  Energy may be stored for use during peak demand by pumping water to a hig-8,;uoc pselm/ w4uinf gy.*jh reservoir when demand is low and then releasing it toju/swg. o n4c8u,- ympi;fl*e drive turbines when needed. Suppose water is pumped to a lake 135 m above the turbines at a rate of $ 1.00\times10^{ 5}kg/s$ for 10.0 h at night.
(a) How much energy (kWh) is needed to do this each night?    $\times10^{9 }W\cdot\,h$
(b) If all this energy is released during a 14-h day, at 75% efficiency, what is the average power output?    kW

  Water is stored in an artificial lake c8r36 f9 lh+prib)p m3nl5zldsreated by a dam (Fig. 15–27). The water depth is 45 m at the dam, and a steady flo5l mp8ds6)9pn z l f+hr33ilbrw 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 qp(s) o7xqsp 7heh3i6 have designed and built an engine that produces 1.50 MW of usable work while taking in 3.00 MW of thermal energy s7 7(6)ophe3 qxshqpi at 425 K, and rejecting 1.50 MW of thermal energy at 215 K. Is there anything fishy about his claim? Explain.  ----待选择----yesno 

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

  A 4-cylinder gasoline engine has an efficiency of 0.25 and delivefa /8xc (zbxduj 4dfo:.ndk u,41jk:krs 220 J of work per cycle per cylinder. When the eng14kcu4bxd: o dk,. /jx8kdjfa n :uzf(ine 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 fromqw04h.a9f*p)smjt i9 guz 2sq the freezer compartm9*hsu2j)qf 9z.4s i gtq0amwp 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 bevm 5jr*rc g1,p 5qsh0q.h ys+g developed that made use of the temperature difference between water at the surface ,gj5sqh m+qc v 1shry*p.g5r0of 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 dire*ce:a4qmok7 octions when they collide and are brought to rest. Estimate tkq:c7a4* meoohe change in entropy of the universe as a result of this collision. Assume $T\,=\,20^{\circ}\,C$    $J/K$

  A 120-g insulated aluminum covw :/hw25p)cofj(*;mj rsb kup 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 an3;bku ixx;on p-6u)kl ideal heat pump that extracts heat l iuo-6;3kpunk);xxb 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 relj(50 -a hgaupfeases 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 lower operating te wz ywx6.1-ad vyzfoy8es(0 g;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 tb kgcbsm -d4.9o state C in Fig. 15–28 for each of the following processes: (a) ADCcmdgbs 4b9.k -, (b) ABC, and (c) AC directly.

  A 33% efficient power plant puts out 850 MW of electrlk5p p7eo1l 9pical power. Cooling towers are used to takep ekp1 l7p95lo 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 steam sy :g1ncj3 latk2nnz+i2(dx.z7cvx 3 goes into the turbines sup3zygl2n3cz2t1j + cn x7iv( dksx a.:nerheated 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 operates at about j /lc8f hne mc 3r:a9h-r/b8f5nvgie* 15% efficiency. Assume the engine’s water temjc:hgc*m3b ir5fev9n 8eh l-8afn//rperature 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 jarri u(p-8pyr,g 5v xxp yx.1*o2z btas7 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 resultsz xs5tnq988pu0s,ojs+ry/p vq 3w (bm 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 conditionaiva1b:tq ol (e1/ t3ger keeps 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 “ i ,xr3lsn;og4 7mxj1prefrigerator with an open door.” The humid air is pulled ini73,l1g js4; xmrxonp 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 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