What happens to the internal energy of watewejeh rfy/5 ppddog15zaj d853y 6 5e8r vapor in the air that condenses on the outside of a cold3drf58515p8aewj5jed yp d /e 6zhygo glass of water? Is work done or heat exchanged? Explain.

Use the conservation of energy to explain why the temperature of a gas increases w4 /jd1yxgy8a when it is quickly compressed — say, by pushing down on a cylinder — whereas the temperature decreases when the g/d 81xgyjy 4waas expands.

In an isothermal process, 3700 J of work is done by an ideal gas. Ise:9( k.*d 2;)twlt egc hludsp this enough information to tell how much heat has been added to t)esu: t ;pgcl.*2 t 9w(dedkhlhe system? If so, how much?

Is it possible for the temperature of a system to re. rh-a-3lomke6k)d ammain constant even though heat flows into or out of it? If6dl3k -.hoea k)amm-r so, give one or two examples.

Explain why the temperature of8ycd :qravi yo3uy 93p,u)(pc a gas increases when it is adiabatically compresseda3 q 8u vy3ucyy9, rp(:cpi)do.

Can mechanical energy ever be transformed completely into heat or internal e wh2rv9:9rax cnergy? Can the reverse happen? In each case, if yourr9w 2r9va: cxh 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 openur-kq/tjy-guz o+ ; 6x? Can you cool the kitchen on a hot summer day by leaving the refrigerator jqktzxgo6;y/+ ur -u-door open? Explain.

Would a definition of heat engine efficie4swlf7f/cwmj ( zp:y 5ncy as $e=W/Q_L$ be useful? Explain.

What plays the role of9xg-c :/)iyfu txj)ry high-temperature and low-temperature areas in (a) an internal combustion engine, and (b) a steam e y:y rtix )cg/)xfuj9-ngine?

Which will give the greateq( gh*yt1i7sxi7r a( z6 rxjg6r improvement in the efficiency of a Carnot engine, a 1qigx 7*sr rji ygh 61(6tazx7(0 $C^{\circ}\,$ increase in the high-temperature reservoir, or a 10 $C^{\circ}\,$ decrease in the low-temperature reservoir? Explain.

The oceans contain a tremendous amount of thermal 5yb i9dcl.*s ldb* 4rn(internal) energy. Why, in general, is it not possible tllcs9*d* yd.4ir b nb5o put this energy to useful work?

A gas is allowed to expand (a) adiabatically and (b) isothermally. In eachki2 3mt3cx o/hw+fli +so1(vv process, does tv3 v1st2oxowfhiclk+ ( +i/ m3he entropy increase, decrease, or stay the same? Explain.

A gas can expand to twice its original volume+sv-gx **x+ro2:ty7 trp8a 6jk tlfs z f2no;w either adiabatically or isothermally. Which process would result in a greater change in entroppx*oyf2vgjf-6x s 8+nrtts *to ;lr+2wa7:z ky? Explain.

Give three examples, 9p3oec ,2uz mz+i u;zqother than those mentioned in this Chapter, of naturally occurring processesqcizu;z, zp9u+ eom3 2 in which order goes to disorder. Discuss the observability of the reverse process.

Which do you think has the greater entropy, 1 kg of solid iron or 1 w1vr52zxtu, /q7/c,piun m16s jr wzdkg of liquid /pis5zq1nwru716 rtu2 ,/w djmz,x vc iron? Why?

(a) What happens if you remove the lid of a bot:*jl mxp8a/b ztle containing chlorine gas? (b) Does thezpbx8*/ jlma : 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 an “in-room air condit 4,z9b ybs1sgaioner”: a big9 14bssybaz g, 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 that this machine cannot cool the room?

Think up several processes (other than those already mentioned) thitd/ x wdhud; 48w4.kuat would obey the first law of thermodynamics, but, if they actually occurrddd;. 4 w8u4/uihkxtwed, would violate the second law.

Suppose a lot of papers ae: secfu 9k6rk *jzz40re strewn all over the floor; then you stack them neatly. Does this violate6ks 0*9 uk:re4z jfcze the second law of thermodynamics? Explain.

The first law of thermodynamics is sometimes whimsically stated as, “You caty3tcnspv5ckcwl 08 ,8 (wbn;n’t get sv,tk (c;wlsbnwn0c8p8yc 53 tomething for nothing,” and the second law as, “You can’t even break even.” Explain how these statements could be equivalent to the formal statements.

Entropy is often called “tis e9 7 8zoqkx/lw(es3nme’s arrow” because it tells us in which direction natural processes occur. If a movie were run backward, name some processes exzkeo9s 78l/q3 n ws(that you might see that would tell you that time was “running backward.”

Living organisms, as they grow, convert relatively simple food molecules intop9+ 5g y3dzb6bhtxl2es0 ixf( 7fwpc1 a complex tx d09 xf iepzsl+5 2pg(hcb1 yb67f3wstructure. Is this a violation of the second law of thermodynamics?

  An ideal gas expands isothermally, perfjz //bo6tz e:bsk2g wqx1g- 9aorming $ 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 maipo t-afp(f :kq7 ;pens .:cdc0ntained at atmospheric pressure. When 1400 kcal of heat is added to the gas, the volume is observed to increase sp.fkppo:7n:t ;c(f-dsc e 0qalowly 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 consta h5cvuf0n 5:aant pressure until its volume is halved, and then it is allowed to expanc5av funa: 05hd isothermally back to its original volume. Draw the process on a PV diagram.

Sketch a PV diagram of the following process: 2.0 L kd xogx174:8u jhx-/me:7dpg ch,dtsof ideal 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 volume until the original pressure is reacheduj d 7/oxg7:h1 xmk4 h:8dp-dex ,cgts.

A 1.0-L volume of air initially at 4.5 atm of (ab5wy )bwex +1ra4tl) njkv18xesolute) pressure is allowed to expand isothermally until the pressure is 1.0 atm. It is then compressed at constant pressure to its initial volume, and lastly is brought back to its original pressure by heating at constant volume. Draw the process on a PV diagram, including numbers and labels for the axej )11ax y 85vween+xwtkbr4l)s.

  The pressure in an ideal gas is cut in half zlrk( bh j:hdnm:h 5)ig auo3 -u.eh+8slowly, while being kept in a container with rigid walls. In the process, 265 h5j8 b.ahmu+d(roile3zgn h:) huk-: 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 adiabatically pm lj-qk+z8x- to half its volume. In doing so, 1850 J of wormp8 q+-kj xz-lk 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 total8m 0pzx6v17 cjw chnu; pressure of 3.0 atm from 400 mL to 660 mL. Heat then flows out of the gas at constant volume, and the pressure and temperature are allowed to drop wnmv1 c zxu6ph 7j;8c0until 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 he6oslb35f ;(rc m r-+(jm *hr sovt+mof an ideal monatomic gas expand adiabatically, performing 7500 J of work in the process. What is the change in temperature of 3m- btm6vrf h o++emo ; rs(j5hl*cs(rthe gas during this expansion?   $ K$

  Consider the following two-step process.*qe3l ;4w(8o oqmaov n Heat is allowed to flow out of an ideal gas at constant volume so that its pressure drops from 2.2 atm to 1.4 atm. Then the gas expands at constant pressure, from a volume of 6.8 L to 9.3 L, where the tempeqoo em8 (3 q*nwvlao4;rature 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)i*+em2u7m- e c fhtxc–23 shows two possible states of a system containing 1.35 mol+if tceecm )2 7m-h*uxes 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 curved path in Fig. 15–f* i:rr)9avck; 6 dbg5zqy7f/ama; pp 24, the work done by the gas isvr; 7c iak b;d*)p g9/yarfm6a5: fpqz $W\,=\,-35\,J$ 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 th 1gmur9el) b5je curved path shown in Fig. 15–24, 80 J of heat leaves the system and 55 J of work is done on thgj b1e )m5rlu9e 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 ( :vacq/yi 4+tuxigeac1)om8 instead of working 11.0 h she took a noontime bre)caea i m:/1yg+o qt (u4vx8icak and ran for 1.0 h?    $ \times10^{ 7}J$

  Calculate the average metabolic lc1q.6rw 3l-, lznsfr rate of a person who sleeps 8.0 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, a.-1rzs l wlrfncq,3 l6nd runs 0.5 h daily.    $W$

  A person decides to lose weight by sleeping one hour less per day, using thephger )0, zq7i time for light activity. How much weight (or mass) can this person expect to lose in 1 )ig7,hre q pz0year, 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 ofektdgr-./ ku2 heat while performing 3200 J of useful work. What is the efficiency of thisgk rdt ue2k.-/ engine?    %

  A heat engine does 9200 J of work per cycle while absorbing 2vcq*:8u(0f6p4 jmkrugdz, v p2.0 kcal of heat from a high-temperature reservoir. Whakp84uj* ,mvc pr (d:vufq06z gt is the efficiency of this engine?    %

  What is the maximum efficiency of a h v hwpx4up..(aeat engine whose operating temperatures are 584pu wxavp (h..0$^{\circ}\,C$ and 380$^{\circ}\,C$?   %

  The exhaust temperat vrxno+g +r;s.ure 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 hx*w/:vkfs vdq ,s /u*theoretical (Carnot) efficiency between temperatures of 62v dsv*/ sx, h*/uk:qwf5$^{\circ}\,C$ 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 thabqo q,wo fw2// md8i)yn ambient tb) fm,qwo i/d8o/q yw2emperature. 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) to the liquid nitrogen “fuel” (Fig. 15–25)?    %(Round to the nearest integer)

  A Carnot engine performs work at the rate of 440 kW while using 680 kcal o0)pns do,( pezf heat per second. If the temperature of the heat sourcodn zp(e ,)0spe is 570$^{\circ}\,C$, at what temperature is the waste heat exhausted?    $^{\circ}\,C$

  A Carnot engine’s operating temperatures are 2/ey- oc78 ha0c 9 ,g2yvnxxhqn10$^{\circ}\,C$ 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.mvsn j .rxgj ;28/kvj electric power. Estimate the heat discharged per second, assuming thatj2xrjv.8 k ;n/s vgmj. the plant has an efficiency of 38%.    $MW$

  A heat engine utilizes a heat source amy l,ggb80 l8mkj; a3pfnf+2 tt 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 exhausp* w-g2tt t( )qysp.cscb*s b zw j3pw(i-5;drts 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 pdrr6u jp2hn p2;d7t /yairs, the output of heat from one being the approximate heat input of the second. The operating temperatures of the first are 67027yd 2r/; 6uhtnjdpp r$^{\circ}\,C$ 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 o w(++sgqx*grtsyk v tblnw2a0 :5f t33f a freezer 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 witb5epo u+,t - ,z.h fvge3tjxt:h a in a 24$^{\circ}\,C$ room. What is the temperature inside the freezer?    $K$

  A restaurant refrigerator has a coefficient of perfn7yy cpk79l sr:px,c1 ormance of 5.0. If the temperature in the kitchen outside the refrigerator is 2:,cls ypy r c7k1x79pn9$^{\circ}\,C$, what is the lowest temperature that could be obtained inside the refrigerator if it were ideal?    $^{\circ}\,C$

  A heat pump is used to keepar ,d nt*9qt-a 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 atp .wn/- 5sudkhk: zj,hf,nbv1 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 effi-mfzu0.; j rc)oe/b u klulb-ui-,go1ciency of 35%. If it were possible to run it backward as a heat pump, what would be its coefficient uf) e/mo l1 c l0.k ub-gu,b;or-u-jizof performance?   

  What is the change in entropg zda2ogr6 :x jg)*b/zy 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 xm pl;uym(.h 2mcb*m/ ;1uiebis heated from 0$^{\circ}\,C$ to 100°C. Estimate the change in entropy of the water.    $J/K$

  What is the change in w* dxr5bamzbp9*y5-htrd 8r-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 initiale fa fhgs:5c.1 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 KE just bef.(b f6z2ve+tnlc o3rwore striking the ground and coming to rest. What is the total change in entropy of the rock plus r6v z.(+t2 eflwbc3onenvironment as a result of this collision?

  An aluminum rod conducts s ;j*ocsrem3 ztoha,u * :l7x;$7.50\,cal/s$ 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 y5zcgoc f6/5b$^{\circ}\,C$ is mixed with 1.0 kg of water at 60$^{\circ}\,C$ in a well-insulated container. Estimate the net change in entropy of the system.    $J/K$

  A 3.8-kg piece of aluminum at 30 t kxjh24lcq95$^{\circ}\,C$ 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 produces:vdo c7jg /(oi.r(za6mbfu -o 550 J of work per cycle for a heat ino7a:z jb-m icu/g d.(ofvor6(put of 2200 J.
(a) Compare the efficiency of this real engine to that of an ideal (Carnot) engine.    % of ideal(Round to the nearest integer)
(b) Calculate the total entropy change of the universe per cycle of the real engine.    $J/K$
(c) Calculate the total entropy change of the universe per cycle of a Carnot engine operating between the same two temperatures.   

  Calculate the probabilities, when you throw two dice, of obtaining waq ,1/mf 2k-l.rjlx :jp,ccobc(os:
(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) xhknlprb ,(38four aces and a l, xh8nbpkr3( 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 microstates and macrostates.

  Suppose that you repeatedly shake six coins in yomyee6* sl+u+ g4svn0x3:e oe fur hand and drop them on the floor. Construct a table showing the number of microstates that correspond to each macrostate. What is the probability of obtaining6yse+3ne e4l o*:f ve+0xs ugm
(a) three heads and three tails,   /64
(b) six heads?   /64

  Solar cells (Fig. 15–26) can produce about 40 W of electricity per squarehusc ee)x *87t meter of surface area if directly facing the Sun. How large an area is required to supply the needs of a e87* xh tu)sechouse 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 durin-hhlx c9aew56 h4pb0 vg peak demand by pumping water to a high reservoir when demand is low and then releasing it to drive turbines when needed. Suppose water c9 4h6 5v0phxb-wealhis 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 creic;dxr*uv ) c/-bz b.xated by a dam (Fig. 15–27). The water depth is 45 m at the . ui*-;/dx) crcxvbzbdam, 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 /c xd3h9pq3 go;9tgv gjp(iq 4that produces 1.50 MW of usable work while taking in 3.00 MW of thermal energy at 425 K, and rejecting 1.50 MW oc t4i/vq j9 (;qgppxh o9dg33gf 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 delivers 220 J o fe 7*f hvzvzea1 icoy9/9p 9)i(zkztm98n-ywf work per cycle per ci79zcp9yvoz/i 9k*y)-ewtz 9n1 f( mvfazeh 8ylinder. 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 ohq;drk5jmcrxd 95mjc6l((2q f a Carnot engine) absorbs heat from the freezer compartment at a temperat(qh6drx52q cm;clrjjkd 5(m9ure 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 developn2wy)mz ef5(f ed that made use of the temperature difference between water at the surface of the ocean and that several hundred meters deep. I mwf5z2ey)(nfn 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 directions when they collr3wv)kg n5 de3(zu a/jide and are brought to rest. Estimate the change in entropy of the universe as a result of this collisn3u 5/gkjvdwrz) 3 e(aion. Assume $T\,=\,20^{\circ}\,C$    $J/K$

  A 120-g insulated aluminum cup at 1k*y42ul kwqhgo; c* swnn(f+-y ay.5psh0p;q 5$^{\circ}\,C$ 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 an5tz7p v8 )tase(b81sko5 dvye ideal heat pump that extracts heat from 6b1oet(s5vt85z7 vkp y eas)8 d$^{\circ}\,C$ 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 carv .hqo*u;fe: x releases about $ 3.0\times10^{ 4}kcal/gal$ If a car averages $41km/gal$ when driving $90km/h$ which requires 25 hp, what is the efficiency of the engine under those conditions?    %

  A Carnot engine has a lower operati/ bds0ca r:z8th j-drcd*/wa3 ng temperature $T_L\,=\,20^{\circ}\,C$ and an efficiency of 30%. By how many kelvins should the high operating temperature $T_H$ be increased to achieve an efficiency of 40%?    $K$

Calculate the work done by an ideal gas in going from state A to s1mnh zdwd- *,jtate C in Fig. 15–28 fjmd1-zwhn *d,or each of the following processes: (a) ADC, (b) ABC, and (c) AC directly.

  A 33% efficient power plant puts out 850 MW of by0p:0 -qphlya9gf7r electrical power. Cooling towers are used 0gp:0phbr-q y7 fa9 ylto 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 dj9/ufhvm61z ljxte ,1w c3 1jfelivers energy 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,eljx1j u1f31 /cth fjwm9 vz6 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 opey2 fm22ix y; d(xq3nvc)k93geap vrm 8rates at about 15% efficiency. Assume the engine’s water temperature of vyyr9fae3dmn) g k c8(p2v 3x;2mqix2 85$^{\circ}\,C$ is its cold-temperature (exhaust) reservoir and 495$^{\circ}\,C$ is its thermal “intake” temperature (the temperature of the exploding gas–air mixture).
(a) What is the ratio of its efficiency relative to its maximum possible (Carnot) efficiency?    %
(b) Estimate how much power (in watts) goes into moving the car, and how much heat, in joules and in kcal, is exhausted to the air in 1.0 h.P =    W $Q_L$ =    $ \times10^{ 9}J$ $Q_L$ =    $ \times10^{5 }kcal$

  An ideal gas is placed in a tall cylindrical jar of cross-sectional area iz c fkhd7k8.fig -3t0$0.800m^2$ 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 ofp rxt wx;d1g;5 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 insidemlu7n5e8uk,ck f * u5e 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 essentjbbu k6uhrbr y;nk81) :gc1 x)ially a “refrigerator 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 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 cbur) c1kunj)8bxhg1b6;r: y k omes 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