What happens to the internal(hahi87k i0 6o8nn00 ipoprfm energy of water vapor in the air that condenses on the ou(f ahm8pp0rko6 007iiin n8oh tside of a cold glass of water? Is work done or heat exchanged? Explain.

Use the conservation of energy to flvoz/ w2z-y 7+5jgf56 cxpe kexplain why the temperature of a gas increases when it is quickly compressed — say, by pushing down on a k7 jlp 2oyfxg56z+fz -vc e/w5cylinder — whereas the temperature decreases when the gas expands.

In an isothermal process, 3700 J of work is done by an ideat .rc*tvu a6h:9l-8w yixu zs cd9.s.ul gas. Is this enough information to tell how much heat htvi.c s. r-uawx.h9l8y9 s t6*du:cuzas been added to the system? If so, how much?

Is it possible for the temperat0,pytyy) 48e/m cjhrwure of a system to remain constant even though heat ,wrh4eyc08yt/ mp)jy flows into or out of it? If so, give one or two examples.

Explain why the temperature of a gas increases when it is adianyrr7i4ne) ,amg+kj 5batically compressedn )kir+y,4 ane75rjgm.

Can mechanical energy ever be transformed completely into heat or int aj c:epea07si.. :etliva87pernal energy? Can the reverse happen? In each case, if a e7jacle.p0as7e8 i:ipt.:vyour answer is no, explain why not; if yes, give one or two examples.

Can you warm a kitchen in winter by leaving the oven doi*ay eryq3: 78:ipc db(bgwz/or open? Can you cool the kitchen on a hot summer day by leaving the refrigerator door open? Explaiy:y/q8g3be w:c(z *di pbai 7rn.

Would a definition of heat engine efficiency ass+59 qnv bwxj; $e=W/Q_L$ be useful? Explain.

What plays the role of high-temperature and low-l+ kh82;4uoihwem. qwtemperature areas in (a) an internal combu u 8+w2himlwoh.;k4qestion engine, and (b) a steam engine?

Which will give the greater improah(blm,kmju//it 7t v0wjq1: vement in the efficiency of a Carnot engine, a /,71k0:vq/t tuljbmwahi( mj10 $C^{\circ}\,$ increase in the high-temperature reservoir, or a 10 $C^{\circ}\,$ decrease in the low-temperature reservoir? Explain.

The oceans contain a tremendous amop17yyl as7q(afx ,y7 vunt of thermal (internal) energy. Why, in general, is it not possibysa7f7a xvy (7pyl,1qle to put this energy to useful work?

A gas is allowed to exr0ns9bjp ,g4 mpand (a) adiabatically and (b) isothermally. In each process, does the entro smjbn0p9gr4, py increase, decrease, or stay the same? Explain.

A gas can expand to twice its original volume eh( x.mmyx:rld ja*.n .ither adiabatically or isothermally. Which proce. hx.xd (jmml. y*:nrass would result in a greater change in entropy? Explain.

Give three examples, other than those mentioned in this Chapter, of natura)el/ei+em s /yj *hn1mlly occurring processes in which order goes to disorder. Discuss the observability of the re/el/s nj1+ h)miy *emeverse process.

Which do you think has the ds; o3mf36h33 2vzqimi oz,usgreater entropy, 1 kg of solid iron or 1 kg of liquid iron? Why?u33hm; v,2smoio3f3dz 6qisz

(a) What happens if you remove the lid of auc)hfznh+e 6* bottle containing chlorine gas? (b) Does the reverse process ever happen? Why or why not? (c) Can you think of two other examples of irreversibilitu ehc+f 6h*zn)y?

You are asked to test a machine that the inventor calls an “in-room air qdf;+ft 4t6t econditioner”: a fdftte+; 6t 4qbig 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 alrey (qjrva/2-o k2d1fnqco8nw1 ady mentioned) that would obey the first law of thermodynamics, but, if they actually occurred, would violate the second- (con/2q q8 o a11rvkndwy2fj law.

Suppose a lot of papers a0/sha0haadim7n bn 4+ re strewn all over the floor; then you stack them neatly. Does this violatnashhi7nma+bd00 4 a /e the second law of thermodynamics? Explain.

The first law of thermodynamics is sometimes whimsically stated as, “You cap( f j9j:p12r,vd 4mxyvnkr1t n’t get something for nothing,” and the second law as, “You can’t even break ever 1fkpyvj,(dmvt4pxn91r 2j:n.” Explain how these statements could be equivalent to the formal statements.

Entropy is often calluy (wvqs0*)-a sn.+ rktkrrs*ed “time’s arrow” because it tells us in which direction natural processes occur. If a movie were run backward, name some processes that you might see that would tell you that timew)qssvk trs+ r0ak*ry-n .(*u was “running backward.”

Living organisms, as they grow, convert relatively simple food molecup/y42fgt e p ;3:apuimles into a complex structure. Is this a violation of the second law ep3m:4; pu agy 2i/tfpof thermodynamics?

  An ideal gas expands isotherma4/6;ml s;wj ag obaut:lly, 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 fitted with aam(f (bde+ nj2 light frictionless piston and maintained at atmospheric pressure. When 1400 kcal of heat is added n df( m(ebja+2to 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 2x:*z knf8ctpte f: n+rd + 4m-st9uxcat constant pressure until its volume is halved, and then it is allowed to expand isothermally back to its original volume. Draw the prox:4 c :29tcd-n+ktes m pnt+8zfru*fxcess on a PV diagram.

Sketch a PV diagram of the followin2 pvv+ v7 5b3c:att ul/bbbn)kedm9/ kg process: 2.0 L of ideal gas at atmospheric pressure are coop+ a97tnemtc/lbv d 3bu :vb)kb5 2/kvled 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 cx;w/pvq.d cc.7 5 ezwtu, ns8initially 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 heating at constant volume. Draw the proces d.;q .p,7 ccvsxwcnu5ze/t8ws on a PV diagram, including numbers and labels for the axes.

  The pressure in an ideal gas bc d;034oxfl1 /o+appznj os*is cut in half slowly, while being kept in a container with rigid walls. In the process, 265 kJ of heat left1pcb/pofz+n * 3o4sd lx ;joa0 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 alm0 so enkx6r/-xost ideal gas is compressed adiabatically to half its volume. In doing so, 1ne6s/kx o0r -x850 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 pr5luqfv1 /tebcrlo, , .5y cx1tessure 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 dr/tvy r1,ob1 f5 xcq.uc,le5 ltop 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 gal4*r b-fo zt-zs expand adiabatically, performing 7500 J of work in the process. W*tr 4-obzzfl -hat is the change in temperature of the gas during this expansion?   $ K$

  Consider the following two-steptj )2a; 6p 2lqx9oxxkh process. 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 temperature reaches its origin2) x9tj;6 xqapo2xh lkal 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 pn9hkbjd)5ml :arx 2ut /ra w;5ossible states of a system containing 1.35 moles of a monatomic idealrj;b/:2nrx ukt dlaa9)mhw55 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. 15–24, p:idq fz9t5bjtr- z9l;5) nucthe work donei)t:tf5 ;-lbnq udjrz p959cz by the gas is $W\,=\,-35\,J$ and the heat added to the gas is $Q\,=\,-63\,J$ Along path abc, the work done is $W\,=\,-48\,J$
(a) What is Q for path abc?    $J$
(b) If $P_c\,=\,\frac{1}{2}P_b$ what is W for path cda?    $J$
(c) What is Q for path cda?    $J$
(d) What is $U_a-U_c$?    $J$
(e) If $U_d-U_c\,=\,5J$ what is Q for path da?    $J$

  In the process of taking a gas from state a to state c along the curved paig2g 04jsgh0* hhjb ,yth shown0g gbiyh*h,hg402sjj in Fig. 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 pers on, /uu 3nnzh x)2k4nuss;to0on of Example 15–8 transform if instead of working 11.0 h she took a noontime break and ran for 1.0 hunsu2x0)zon4 nk/ ,tu;n3 sho?    $ \times10^{ 7}J$

  Calculate the average metabolic rate of a person who sleeps 8.0 h, sits gp (3jx4wq4ds.n o+h qat a desk 8.0 h, engages in light activity 4.0 h, watches television 2.0 h, plays te (wn.sqd4o q p3j+h4gxnnis 1.5 h, and runs 0.5 h daily.    $W$

  A person decides to lose weight by sleeping one houingnzt 1;iu;uw--t 7 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 intake? Assume that 1 kg of fat stores about 40,000 un tnigzit-w -1u;u 7;kJ of energy.   kg(retain one decimal places)    $lbs$

  A heat engine exhausts 8200 J of heat while p a*gtakl*/ksb da.;0jerforming 3200 J of useful work. What is the efficiency of this enl s.a0kda kg; baj/t**gine?    %

  A heat engine does 9200 J of v hi92bu9n/thikaq ho+g3 ;i,work per cycle while absorbing 22.0 kcal of heat from a high-temperature reservoir. What is th /+in9bu3tih2k aqv9 hg, oih;e efficiency of this engine?    %

  What is the maximum efficiency of a heat engine whose operating temperaturzplbvi+ *+u3rm - g:gies are 580gvil*u+: i 3br +p-zgm$^{\circ}\,C$ and 380$^{\circ}\,C$?   %

  The exhaust temperature of a heat5x+.zsn(d. )kzc tlhj 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 ;7w3wo: gy-pi5 y :4sc2a rt,zizbxoe maximum theoretical (Carnot) efficiency between temperature35zaetox7:-ro;iyiy c wp2 , sg:b4wzs of 625$^{\circ}\,C$ and 350$^{\circ}\,C$. If the plant produces electric energy at the rate of 1.3 GW, how much exhaust heat is discharged per hour?    $ \times10^{13 }J/h$

  It is not necessary that a heat engine’s hot environment be hotter tha4zd / mev;;4xtqycve*n ambient temperature. Liquid nitrogen (77 K) i ;xe qd/c;e* myt4zv4vs 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 dx//x nk m qzz)k4fn.3kW while using 680 kcal of heat per second. If the temperature of the heat source 3 zkfnzk)n/qdm/. xx4is 570$^{\circ}\,C$, at what temperature is the waste heat exhausted?    $^{\circ}\,C$

  A Carnot engine’s operatin* iqnqtv p4v c-3-,ktng temperatures 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 M446n kyfw jetu*l9pc58cv z3kW of electric power. Estimate the heat discharged per seconzvuc3weltk4 5cy jpkf 6*948nd, assuming that the plant has an efficiency of 38%.    $MW$

  A heat engine utilizesrqt-kok, rb+/hn h4 k6 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 dqf0qa8 xk.6 5oradu1heat 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, g utfbds/qy(;*)12b +o gmkohsteam engines work in pairs, the output of heat from one being the approximate heat input of the second. The operating temperatures of the1g )kbuq;m /dsboh+2g*to f (y 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 f sc53)ekc;kv:6o-5 q5eb/azfx lkm kt reezer 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-frekt glz+z;dy 5;ezer operates with a in a 24$^{\circ}\,C$ room. What is the temperature inside the freezer?    $K$

  A restaurant refrigerator haseg yr5 ( 1zb4i7uful,7 ahh1ca a coefficient of performance of 5.0. If the temperature in the kitchen outside the refrigerh i5ucz4(, ahyeuar1f1 7 g7blator 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 ho7s;vam4/n6az nt9cxq use 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 as,9y(lv b6 bsz)iy)jst 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 *u+s:82oy )li mfdkjlto run it backward as a heat pump, what 8l :yd)i +mf 2luoks*jwould be its coefficient of performance?   

  What is the change in tcl2xi7mm*9 n entropy of 250 g of steam at 100$^{\circ}\,C$ when it is condensed to water at 100$^{\circ}\,C$?    $J/K$

  One kilogram of water is hw;gqbf tj .q3hlgg7( 6pm-2ka3o y ik:eated from 0$^{\circ}\,C$ to 100°C. Estimate the change in entropy of the water.    $J/K$

  What is the change in en4iu+; trn 270axmaakztropy 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 anvh3 p5roe u zc6m-0ae- initial 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 beforeoswbk/u ) xtr(ks7xbl )46ju4 striking the ground and coming to rest. What is the tot/lk jbu4s7o r6 k xx)su)4(wbtal change in entropy of the rock plus environment as a result of this collision?

  An aluminum rod conduct yi5z hn7lrgam6lhgk5 ,1n/eiz1 w6r4s $7.50\,cal/s$ 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 3; j)fwf,+f pdk0$^{\circ}\,C$ 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 d,o zxk 63low4 qyw73wat 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 workingx k4;myq,lz lg00k/fiyx 93fa between heat reservoirs at 970 K and 650 K produces 550 J of work per cyx,a myff/0yl4xzq 3gk 0l;ki9cle for 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 probabilitieob(+,;wa od( dqxq7y ks, when you throw 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 increasing prot30y9zx3 ccaybability: (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 microstates and03cya c xyt93z macrostates.

  Suppose that you repeatedly shake six coins in your hand andek ;- ch1;gjw5 vvbkp k8uiw:9 drop them on the floor. Construct a table showing the numbe9gkkv bi8 w;vj1-wce;uk5 p h:r 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 elj-dtj 2p/ 1e- pdy1zemectricity per square meter of surface area if directly fd/z-j1- et2jm 1dp pyeacing the Sun. 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 demau( qw. rfb sru,m62jv7nd by pumping water to a high reservoir when demand is low and 6usjr(mb wf2uv,q7r.then releasing 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 water p+z/; la3f /vbd4eo;r:zbrkn depth is 45 m at th3:;boa/dz enk/frr;+ p b lzv4e 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 of2ghb5 yzx03mgj lex2)rkv : k3 hbsw6/ 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.ghzb ksg6 3 w:3/e xkvrlxh y25jbm20) 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 en.hx-e3bdwnd96xf(h ag5 (o e dgine has an efficiency of 0.25 and delivers 220 J of work per cycle per cylinder. When the engin.ddn(h9 efx 3dw- 5gob 6ae(xhe 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 engineuxl)db(wbn;fu u ( /o0) absorbs heat from the freezer compartment at a temperature of -( ;bbof (/x0uunul)dw17$^{\circ}\,C$ 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 useo5zt1cg9/i2azku0f 3a*rfkm of the temperature difference between water at the surface of the ocean and that sevz9m/*5ao t02ckr z13guff ikaeral 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 tr*toer 6xf-bs, aveling in opposite directions when they collide and are brought to rest. Estimate the change in en-bo6tsfre,x *tropy of the universe as a result of this collision. Assume $T\,=\,20^{\circ}\,C$    $J/K$

  A 120-g insulated aluminum c-d;; bt :ask(flac54k4urin tup 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 puu(dr fawb ,eh*3f7 m3wd4ft0zkf-m 7kmp that extracts heat fro fr zbd0w,ht fu(kk3m af7m4e3 w*d-7fm 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 inc+hxj/g,7ja4n ,ljbcg* c * og a car 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 operap ra5,gegp5 3sc yq9x*ting 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 state C jzj 6wilk/0m h 8jty41ll17t p3fg8uu in Fig. 15–28 for each o mt81w 1tg3hj ul 76zyl04/l8kujjifpf the following processes: (a) ADC, (b) ABC, and (c) AC directly.

  A 33% efficient power plan mnf.7 *v-qdvhr5v ka0t puts out 850 MW of electrical power. Cooling towers are used to take away the exm fhvrq* a v0dn.75k-vhaust 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 dt 1 p9mbq4j:wsteam turbines. The steam goes into the turbt qwmp:41 j9dbines 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 aboutj.g -k86 exkoh 15% efficiency. Assume the engine’s water temperatur.kxehj86 g- koe 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 placedc7a5in:j twc( in a tall cylindrical 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 fahh ye+;bn 7y*bt results in about $ 3.7\times10^{7 }J$ of internal energy in the body.
(a) In one day, how much fat does the body burn to maintain the body temperature of a person staying in bed and metabolizing at an average rate of 95 W? $\approx$ =    $kg/d$(retain two decimal places)
(b) How long would it take to burn 1.0-kg of fat this way assuming there is no food intake?    d

  An ideal air conditioner keeps the temperature inside a room at dx,t1uzqc j7,ef ge7vpv1 y-qcmm;*-gs )8wm 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.” The humid air xgz6i ;he rm,cte:n)mr+*8xqx: t,qcis pulled in by a fan and guided to a cold coil, where the temperature is less than the dew point, a : zx:);8,geem mcn+crtqrqt, *xx i6hnd 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