What happens to the internal energy of water vapor in the air that *cty-bart6i90e, : :rbsttzd shg(d. condenses on the outside of a cold glass of water? Is work done or hea-s:ehr*dyzb9 tctsgt abi, :d0 t6r(.t exchanged? Explain.

Use the conservation of energy t)o eyahh)x(q ;o explain why the temperature of a gas increases when it is quickly compressed — say, by pushing down on a cylinder — whereas the temperature deo);qe x (a)yhhcreases when the gas expands.

In an isothermal process) au2 (*njq, zfe x2edrt5t8q/ xin:wz, 3700 J of work is done by an ideal gas. Is this enough information to tell how)8ar:if ,*t/z2jneu wn5 ex t(x2qd zq much heat has been added to the system? If so, how much?

Is it possible for the temperature of o5su(rkn z2yy 5r d,1fa system to remain constant even though heat flows kyrosrn1f ,d 2 zyu55(into or out of it? If so, give one or two examples.

Explain why the temperature of a gasbh6nq)g;48k42quryn bfnw njo 7m/f ) increases when it is adiabatically compressedh64))quq ojwbm24nkfg yn 8 nrn/7;f b.

Can mechanical energy ev:)-1r 0hqddg2du cycier be transformed completely into heat or internal energy? Can the rd:c c) id1u0qh2yd- greverse happen? 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 ovenicc8dw5/ye.m u ra.e/ door open? Can you cool the kitchen on a hot summer day by /a u.8ier5mwyccde. / leaving the refrigerator door open? Explain.

Would a definition of heat engine efficienckiqms;ok x uh :89-rj1y as $e=W/Q_L$ be useful? Explain.

What plays the role of hig*jxt;god3*ug m z(6vlt .a e/dh-temperature and low-temperature areas in (a) an internal combustion engine, and (/ut .t*gx zo;m*jd(eg l 3dv6ab) a steam engine?

Which will give the greater improv;ii/b.0w -jmx :xou ztement in the efficiency of a Carnot engine, a tw:z/0mb-i j.xxiou; 10 $C^{\circ}\,$ 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) energygid n-lh cf7z9td6. 2o. Why, in general, is it not possible tof62 7i. doztl9nc -dgh put this energy to useful work?

A gas is allowed to expand (a) adiabatically and (b) isothermally. In be yfgm2f4iflq;+)7g6rwl m/ each process, does the entropy increase, decrease, g;)4rlqmw/2f bfl mgyf6 ei 7+or stay the same? Explain.

A gas can expand to twice its original volume either 7 : 4vonzl gywg0-rg7gadiabatically or isothermally. Which process would result in a vgo0-7:gygl4 zr w7gngreater change in entropy? Explain.

Give three examples, othert0pd fc0(1ul ume81 ki than those mentioned in this Chapter, of naturally occurring pul(u0 1mtie10pc8kdf rocesses in which order goes to disorder. Discuss the observability of the reverse process.

Which do you think h6c lca(zacwq,)0wu n8as the greater entropy, 1 kg of solid iron or 1 kg of liquid iron? Why uc wc6c,8aqaznw0l)( ?

(a) What happens if you remove the lid of a bottle containing chlorine gas? (b) *c v97-.cg eyv k9dou cczfem+n27ed2Does the reverse process ev2e+.k-9c cyudeo z fc7ncve2g9vd*m 7er happen? Why or why not? (c) Can you think of two other examples of irreversibility?

You are asked to test a machine that the inventaj w10c a4r:i:vhf9f+ (qmggqor 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 switched on, you feel a stream of cold air coqafqrj+m cvfh ( ia1 ::9wg0g4ming out of it. How do you know that this machine cannot cool the room?

Think up several processes (ot .h5b+2xuow vkher than those already mentioned) that would obey the first law of thermodynamic5vk+h w u.obx2s, but, if they actually occurred, would violate the second law.

Suppose a lot of papers are strewn all over the floor; then hq0pnedbibyy-fz365- 4c9u,h3f cnryou stack them neatly. Does this violate the second law of thermodynamics?y6,he n 35f- c-zhbuip 30fqn4 9rycdb Explain.

The first law of thermodynamics is s4x84hsij-mj)k i17yqmvz,o x7p v g0zometimes whimsically stated as, “You can’t get something for nothing,” and the second laws4147 0 vhzp)imkiz8j7j,g x mox vyq- 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 it tells us in whqea ij fymhpf l*ysbo4( 82r(8 wyz0y(t,)wz3 ich direction natural processes occur. If a movie were run backward, name some processes that you might see that would tell you that time was “running byqzwa(hrw ij 2)p8,zob yt (f3(8y mlyse 0*4fackward.”

Living organisms, as they grow, convert relatively simple food mk.k v0noxf tyt l1 ;,iv6/8 ym0cnmw;dolecules into a complex i 0 nvy l.yc wt86;v;kxm10n,ftokdm/structure. Is this a violation of the second law of thermodynamics?

  An ideal gas expands isothermad5v rt;xyb,w /8rew b5lly, 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 cylinder lxu nz3343mqw+m zkl+fitted with a light frictionless piston and maintained at atmospheric pressure. When 1400 kcal of heat ikqz3l4 w3um+m3 z+nlxs 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 coh dv++*eul s1) s/y0w8tdesxlnstant pressure until its volume is halved, and then it is allowed to expand isothermalld l *welv/s) s x+u+h10tsdey8y back to its original volume. Draw the process on a PV diagram.

Sketch a PV diagram of the following process: 2.0 L of i* me u d/eoy: lmnnhl.y+98yz2deal gas 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 is increased at constant vollyzn*/hulndye 2m 9 e+:.o8ymume until the original pressure is reached.

A 1.0-L volume of air initially at 4.5 atko(d sm8 g3rs0m of (absolute) pressure is allowed to expand isothermally until the pressure is 1.(mk ds0or8 3sg0 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 con 0qjf6dcu-d gsrh 9w5q(bfi2cgoe5/*tainer with rigid walls. In the/g50sfj2ecd5-id6 wqu(*cro hb9f q g 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 ide+s;:f0wh 9 cnfwj1cj; 6wghhwal gas is compressed adiabatically to half its volume. In doing so, 1850 J of work is done h+0c;w6f w; s wgn:jwh9 1fhcjon 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 p dkxx/ 1-r pq:jffvs; 5z6f3lq6+whv yressure of 3.0 atm from 400 mL to 660 mL. Heat then flows out of the gas at;d61pf-xhfwvq kv sf/x6j: l3y+r qz 5 constant volume, and the pressure and temperature are allowed to drop until the temperature reaches its original value. Calculate
(a) the total work done by the gas in the process,   $J$
(b) the total heat flow into the gas.    $J$

  One and one-half moles of an ideal monatomic gas expand adiabatically, perf ,w0:2r*ju bebkgadc6orming 7500 J of work in the process. What is the change in temperature of the gas during thisjg 2bbw0:kud ,6er*ac expansion?   $ K$

  Consider the following two-step procei2 6z1 w qphhrv bq.brmk87,-lss. 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 rwi6b q,hzp81-.krlmqvh 7b 2 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 possible states of a system contait0eae-3te,mwp f7nu6v( loud.)0:f mbz t(bp ning 1.35 moles of a monomfbav n e.:ft(uuz-d,7m0tet e)p6bl0p( 3 watomic 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 alk9 c qfcl8f+(wong the curved path in Fig. 15–24, the work done by the gas i89c fclqw f(+ks $W\,=\,-35\,J$ 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 curckcpbvk + s-gbbr (*q0: 82cf( ;qf88hsauvbzved path shown in F2 s:cab8vqkbg ck+-(c8*brf hfp vbq8z u(0;sig. 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 transforml.y; d:tiplan v2v) 1mlvdy(hw u 92y1 if instead of working 11.0 h she took a noontime break and 2(9p; ta1lvv2dldu.hl) nwmyy: y1v iran for 1.0 h?    $ \times10^{ 7}J$

  Calculate the average metabolic rate of a person who st*s,4qi oz eb5leeps 8.0 h, sits at a desk 8.0 h, engages ite,4iz s b*q5on 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 hour less per day, usin7b0s6gvudt : ) bxjx/ag the time for light activity. How much weight (or mass) can this person expect to lose ixsj/d)6vg xtbau7b: 0n 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 3200 J of useful worwt:iae6a4o uft7 bp3 h2 zz n,f(m:9sxk. What is the efficiency of thi3a4x9u efo,f7sp2twbzaht:z 6 m i n:(s engine?    %

  A heat engine does 9200 J of work per c8hoy*8; bzg):l azz6x6 pfpjhycle while absorbing 22.0 kcal of heat from a high-temperature reservoir. What is the efficiency of this enginpaf6gz y6 *; )b8zo:h8plxjhz e?    %

  What is the maximum efficiency of a heat engine whose operatinpe0 l wi6-*oz*4 pistcg temperatures are 584z s l0*p tp-e6iiocw*0$^{\circ}\,C$ and 380$^{\circ}\,C$?   %

  The exhaust temperature of a heaun n.-6,e0ea2 i nznlq ,fld8 jbid;b-t 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 (Caryu) 9(sv-8 cn;og5vpvoaoc( znot) efficiency betweo)cz8g vcvu y5n9o ap(;so-v(en 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 termr78w ij n1(,dd w8mhat a heat engine’s hot environment be hotter than ambient temperature. Liquid nitrogen (77 K) is about as cheap as bottled water. What would be thnei 1m , r8dw7(j8rmdwe 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 performs0l 2e yfo n 3e9(f.sds14 w-g7bkmflgk work at the rate of 440 kW while using 680 kcal of heat p nfgkkofgd4sl(- .3ly7s0ee b 9f m2w1er second. 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 temperaturesu4(zs* fjrx2x lj b rp8iq;l6/ 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. Estim;or-, 3)pvtrn dobuo2qad u9 3ate the heat discharged per second, assuming that the p,o3 apu)d9-;uo3qn b vro td2rlant has an efficiency of 38%.    $MW$

  A heat engine utilizesp(+/uwb p uqs9 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 heat at 35t;d)ps snh3nl(e:cc1b, uvwr: cp7/a9;ks hy0$^{\circ}\,C$ 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 paiqsql78b18,y jvlcyh z;p/ 3 ks28x hgfrs, the output of heat from one being the approximate heat input of the second. The operating temperatures of the first fpq8 sb 1kvh/qz;ysj gxc2l7 ,yl 38h8are 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 fr wchg,,+ lmnv(eezer 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 a 24w u/dn21,gv-4n k elik$^{\circ}\,C$ room. What is the temperature inside the freezer?    $K$

  A restaurant refrigerator has a coefcf0o onzlzkct7. .r;)ficient of performance of 5.0. If the temperature in the kitchen onccr.kfz z t. lo7o;)0utside 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 hocvlo el:k x*(q2t(ye0use 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 at0 rlubk.6rg,ibt 2x9 by;upe 3 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 a6smg hs;x(o -xn efficiency of 35%. If it were possible to run it backward as a heat pump, what would be its coefficient of pm(;-g 6s xhsoxerformance?   

  What is the change in entropy of 250 g of sw :)5*g3ow 8wisfnlwiteam at 100$^{\circ}\,C$ when it is condensed to water at 100$^{\circ}\,C$?    $J/K$

  One kilogram of water is hea/4q mzoucig) 5hut *e(ted from 0$^{\circ}\,C$ to 100°C. Estimate the change in entropy of the water.    $J/K$

  What is the change in entropy of -+rf4uorgd -sbb j:x,el y azx9y1(4h$1\,m^3$ 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 speed of d:out qygdeeh/9 h .)x*d0 nfhaa-++c $3.0m/s$ 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 :zwuoi497;pvzu0h re4yf.zjrl4n h( striking the ground and coming to rest. What is the total chlf0hvu7 e ;i on:r y( z4wupjrh4.9z4zange in entropy of the rock plus environment as a result of this collision?

  An aluminum rod conductrfzwv) m) 56*e;ppixbcofz5 5 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 30lz5gn ivqrbj20 j 796hu2p 8qt$^{\circ}\,C$ 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 alumvy+no zn;p qio*.+ *pminum at 30$^{\circ}\,C$ is placed in 1.0 kg of water in a Styrofoam container at room temperature (20$^{\circ}\,C$). Calculate the approximate net change in entropy of the system.    $J/K$

  A real heat engine working between heat reservoirs at 970 K and 650 K 5bhk7s y qbi7u8 (qce4sqw/*cproduces 550 J of work per cycle forsqw q u78eib(yc4qbh s /kc75* 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 diceq.rz z+bg0zrd0.o1gbkf5bne+2 7k fi , of obtaining
(a) two numbers totaling 5. The probability is 1/  
(b) two numbers totaling 11. The probability is 1/  

Rank the following fi hoxh6k/*w q,waq.bd( el10g rve-card hands in order of increasing probability: (a) four aces and a king; (b) six of hearts, eight of diamonds, queen of clubs, threr w ,qx(h*ho0eg/dlk.b 6qw1a e of hearts, jack of spades; (c) two jacks, two queens, and an ace; and (d) any hand having no two equal-value cards. Discuss your ranking in terms of microstates and macrostates.

  Suppose that you repeatedly shake six coins in your hand and drop them(d:8n ndqr7lh::r xsn on the floor. Construct a table showing the number of microstates that correspond to each macro :srnx 8nhnrd :d(l:q7state. What is the probability of obtaining
(a) three heads and three tails,   /64
(b) six heads?   /64

  Solar cells (Fig. 15) zbo ;(ywc6 m8q7.;vl xfvlse–26) can produce about 40 W of electricity per square meter of surface area if directly facing the Sun. How large an afv ()v.8 ;;q6ywcxls7boelmz rea 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 highcbh/e cm,;qp+78 oboo reservoir when demand is low and then releasingob7/;mp ooecq 8 bch+, it to drive turbines when needed. Suppose water is pumped to a lake 135 m above the turbines at a rate of $ 1.00\times10^{ 5}kg/s$ for 10.0 h at night.
(a) How much energy (kWh) is needed to do this each night?    $\times10^{9 }W\cdot\,h$
(b) If all this energy is released during a 14-h day, at 75% efficiency, what is the average power output?    kW

  Water is stored in an artificial lake created by a dam (Fig. 15–27). The wateocurj 6ld3o;w )6bm(rxk np- :r depth is 45 m at the dam, and a steady flow ratlxcdo 6p;m)un :3jrro -(k wb6e 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 pronp2r4r7 ss + xxofz7.bduces 1.50 MW of usable work while taking in 3.00 MW of thermal energy at 425 K, and rejecting 1.50 MW of thermal energy at 215 K. pr7+ bosfx72znsx 4r .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 deliv,cc) 8t6 elydvers 220 J of work per cycle per cylinder. When th6ey)l 8cv, ctde 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 reverqm51u3b d5nij :9qy3c abuy/rsloj0 7 se of a Carnot engine) absorbs heat from the freezer compartment at a temperatureasn 5705j9:1q 3 buiy3drjmcyboql/u 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 use of thc).,ubd9 -hixo yfp:3vcghd( e temperature difference between water at the surface of the ocean and that several hundred meters deep. In the tropics, the temperaturd-dp3hf iyxobu9)h,.c cvg :(es 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 +z+shhmqhtvhgzk*f/0y (,0copposite directions when they collide and are brought to rest. E ys0*z,hq /c+v+(mk f0tzhhhg stimate the change in entropy of the universe as a result of this collision. Assume $T\,=\,20^{\circ}\,C$    $J/K$

  A 120-g insulated aluminum cupj*fy6lmug i 9bko42i* at 15$^{\circ}\,C$ is filled with 140 g of water at 50$^{\circ}\,C$. After a few minutes, equilibrium is reached.
(a) Determine the final temperature,    $^{\circ}\,C$
(b) estimate the total change in entropy.    $J/K$

  (a) What is the coefficient of performance of an ideal heat pump that extracts:n) o:+9r jzac+e(j e1t m vp8ofvilv8 heat frifnv p+erjo()vt8zm 9c ojv 1::+ae l8om 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 aboutud8b1 mss am16 $ 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 opepznof d-ddbjb. rs5)tt 0l6vm51xt4 6rating 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 dokzqleiop*s xfq/h+ j 7hy6 8,8ne by an ideal gas in going from state A to state C in Fig. 15–28 for each of the following processzkxjqf*y8l6h+8es,i h/ o7p qes: (a) ADC, (b) ABC, and (c) AC directly.

  A 33% efficient power plant puts out 850 MW of electrical power. Cooling ;o2; pxg9npv48jwyvj towers are usj;w248pxog pj;v n9vyed 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 energy at 980 MW using a,+ yr j4n*a/:6 iiohnbf) tgysteam turbines. The steam goes into the t,t *ga4+ynfjih :o a)/6rybinurbines 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 operates at about 15% efficiency. Assume the enp4 9uq*fip tev +wv9n tf1qg;zgo /u),gine’s water temperature of /9nuu q;pt v49q *tvi1 ,ep)fgzg+owf85$^{\circ}\,C$ 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-seqiwuq 7l5v9 hil3:rug ;, w;sactional 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 fatvlju)ud j/42x2l3ebj 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 thc y9g0x8 p):fq8excwcl ,pq+e6 s5vm le 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 wiw ibcag 5f1k;sqlc ll(n/.3j1th an open door.” The humid air is pulled in by a fan and guided to a cold coil, where the temperature is less than the dew point, and some of the air’s water condenses. After this water is extracted, the air is warmed back to its original temperature and sent into the room. In a well-designed dehumidifier, the heat is exchanged between the incoming and outgoing air. This way the heat that is removed by the refrigerator coil mostly comes from the condensation of water vapor to liquid. Estimate how much water is removed in 1.0 l cca;(ljb3k/ng. s5 f1qwli1h 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