What happens to the internal energy of water jc guj.i-((wnvapor in the air that condenses on the outside of a cold glass of water? Is work done or heat exchanged? (ugw-i.c j(jnExplain.

Use the conservation of energy to explain why the temperature of a gg su -kpha)15kas increases when it is quickly compressed — say, by pushing down on a cylinder — whereas the temperature decreases when the gas 5g )khskup- 1aexpands.

In an isothermal process, 3700 J of work is done *ybb,2j1d9nugje. nux 1dv2 el6v2e d by an ideal gas. Is this enough information to tell how much hvdeey .vbnbn2u 9 jde612* g,l21udjxeat has been added to the system? If so, how much?

Is it possible for the tempjip/o5x ly: xwb1h 6,tli:v6serature of a system to remain constant even though heat flows into or out of it? Ihxv5wl io,:x:6 sj l piytb61/f so, give one or two examples.

Explain why the temperatuqlq u f+n,gvt0,0r: mmre of a gas increases when it is adiabatically compresseq,ntg,mv0u+0m r:qf ld.

Can mechanical energy ever be transformed completely illgc,oi+k2 - x6ch+jn nto heat or internal energy? Can the reverse happen? In each case, if your answer is no, explain why no+,ic6+ kgh2clj ox- nlt; if yes, give one or two examples.

Can you warm a kitchen in winter by leaving the oven door open? C/ up ugr37ug;:jxl6z gan you cool the kitchen on a hot summerx3u grg7j/pu :;guzl 6 day by leaving the refrigerator door open? Explain.

Would a definition of heat engine efxl fhrg5 ah5 m3,ry*/lficiency as $e=W/Q_L$ be useful? Explain.

What plays the role of high-temperature and low-tempejaz,ydtq,6 ( xrature areas in (a) an internal combustion engine, and (b) a steam enginjq(x,ta z d6y,e?

Which will give the greater improvement in the effici 8vgzgo/p-t ahyrn d7/0h1)ys ency of a Carnot engine, a 10 -1v p)ag 7hho g8/z sy0t/dynr$C^{\circ}\,$ increase in the high-temperature reservoir, or a 10 $C^{\circ}\,$ decrease in the low-temperature reservoir? Explain.

The oceans contain a tremendous amount of thermal (internal) energy. Why,,9v o(3iep*b z6qtdk m9xv5dp q*vsp5 in general, is it not possible to put this evip3v(z s kqo,dbp6pt5*m9q9 d * vx5energy to useful work?

A gas is allowed to expand (a) adiabatically and (b) isothermallzm-xpjd8o*u148;pzn w 5 coq ky. In each process, does the entropy increase, decrease, or stay the same? Explaixmj;cq*-o8 o5 8zdz wp 4nu1kpn.

A gas can expand to twice its original volume either adiabatically or isothefu1a 5wl 4igp 4pkc 86qv noed856vhq7rmally. Which proc6hv 65vew8a 5748 c gqnuipdqpf14 okless would result in a greater change in entropy? Explain.

Give three examples, other than those mentioned in this Chapter, of g 2: e4equxda*h7)ihwnaturally occurring processes in which order goes to disorder. Discuss the observability :2dui7hq*w 4ehag e)xof the reverse process.

Which do you think has the greater entropy, 1 kg of solid iron or 1 kgbavp)78 c/k4jdbbc 3m of liquidk bjb3cm pa7b8v c)d4/ iron? Why?

(a) What happens if you remove the lid of a b1gv3cqn((k, zs ;viqqottle containing chlorine gas? (b) Does the reverse process ever happen? Why or why not? (c) Can yzn g(c vk ,1q(;3vqiqsou think of two other examples of irreversibility?

You are asked to test a machine that the inventorlff do3rh 44p* calls an “in-room air conditioner”: a big box, standing in the middle of the room, w *h 4d4o3rffplith 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) that would obey90 icz/pe op;dtb4zc*ox 1o e1kw:(cm the first law of thermcc9w *4zco i/0dx1p ;:ketozm bp 1o(eodynamics, but, if they actually occurred, would violate the second law.

Suppose a lot of papers are strewn all over the okt6.su( s9svfloor; then you stack them neatly. Does this violss69vk(.tu soate the second law of thermodynamics? Explain.

The first law of thermodynamics is somro1z4qgl yr.q r-zmb9-/r u j(etimes whimsically stated as, “You can’t get something for nothing,” and the second law as, “Yro. q4jym gu(-r/bqr z lz9-1rou 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 u;s gb0b09g bnzp42fv ls in which direction natural processes occur. If a movie we0 lp09z4 vg2sn g;bfbbre run backward, name some processes that you might see that would tell you that time was “running backward.”

Living organisms, as they grow, convert relatively simple food molecules int -lmtp;n(g pw1o a complex structure. Is this a v -wl(1mpgtn ;piolation of the second law of thermodynamics?

  An ideal gas expands isotheiz9q dep.2fp- p x7t-;cziw1qrmally, 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 inlu*se 3 5leu*ts4) idp a cylinder fitted with a light frictionless piston and maintained at atmospheric pressure. When 1400 kcal of heat is added to the gas, thel *t3dses*e 4)i5puul 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 constant pressure until its vol-ncfr5 edm r: v+5o2-6clwvfeume is halved, and then it is allowed to expand isothermally back to its original volume. e5-wr l2v+o-:cerf vmn 5fdc6Draw the process on a PV diagram.

Sketch a PV diagram of the following process: 2.0 L of ideal gas atm(p57*/qzs,zjak3nvl o *kq n atmospheric pressure are cooled at constant pressk,qns **l(p7j znoam/q 3kz v5ure 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 initially at 4.5 atm of (absolute) pressure is allowedbh m(+o; s jvg5n1j0tg to expand isothjv(h gg jbs+50tnom1; ermally 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 axes.

  The pressure in an ideal gas is cut in half slowly, while beinbf-:ok*n.b ss g kept in a container with rigid walls. In the process, 265 kJ of heat left the n -bo.:skb*sfgas.
(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 to half itsk/clkurw mm/12k+7zs volume. In doing so, 18502ksmzkwm u/rc7k/1+l 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 covt-2u- t cnzen2 w(f*snstant total pressure of 3.0 atm from 400 mL to 660 mL. Heat then flows out of nzfc2-*uvnw-2t st( ethe gas at 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 mole 1k)n3mcd(*v3l nx,hztki1 wu s of an ideal monatomic gas expand adiabatically, performing 7500 J of work in the process. What is the change in vzu1n1*),k 3xm3 dnw t klihc(temperature of the gas during this expansion?   $ K$

  Consider the following two-step processm28:-txm(qemvk (j sv. Heat is allowed to flow out of an ideal gas at constant volume mmj(kx: qv(s m2tv -e8so 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 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 shuxx i0 tm:mg,-ows two possible states of a system containing 1.35 moles of a monatomic ideal mt -iu, 0gx:xmgas.$(P_1\,=\,P_2\,=\,455N/m^2,V_1\,=\,2.00m^3,V_2\,=\,8.00m^3)$
(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, the wore3u() u pnfn-mk done by the gu)-u n(mf ne3pas 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 sta6 re. xx5 lg7tdk+h2kyte c along the curved path showr+2l xtg657kkx.hd ey n 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 person of Example 15–8 transfok h; ntnx/8k2zrm if instead of working 11.0 h she took a noontime breakt n;kn2k /zh8x and ran for 1.0 h?    $ \times10^{ 7}J$

  Calculate the average metabolic rate of4v+c; 0+hwqc0,e5 vi bxio9wqztwoih2 o an)* 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, and runs 0.5 h w chi ,wvoicoqie9qv+a)4bz*t+0;h no20xw 5daily.    $W$

  A person decides to lose weight by slexzw 0dgq :8gm 4fdc;tzf4m3h 5yz,7cweping one hour less per day, using the time for light activity. How much weight (or mass) can this person expect to lose in 1 year, assuming no change in food intake? Assume that 1 kg of fat stores about 40,000 kJ of ener8xhcqffz zc,md3 5 t4g40mw7dg y:z;wgy.   kg(retain one decimal places)    $lbs$

  A heat engine exhausts 8200 J of heat while performing 3200 J o x6ph(e8 dbxq2f useful work. What ed8bx hx2(6pqis the efficiency of this engine?    %

  A heat engine does 9200 J of work per cycle while absorb r9ytp2d-au2mv :)a qaing 22.0 kcal of heat from a high-temp9mq2 2 y rtv:-dapaua)erature reservoir. What is the efficiency of this engine?    %

  What is the maximum efficiency of a heat engine whose operating ta; x,af k6sf0wemperatures aresa,f0kawx; f6 580$^{\circ}\,C$ and 380$^{\circ}\,C$?   %

  The exhaust temperature uy:( lh6: stjcof 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 itt,i r58m jga;+w 6oqsss maximum theoretical (Carnot) efficiency between temperatures of 625 g qrto8am+i wj,5s;s6$^{\circ}\,C$ 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 heagwtxv(dv97red(p,c+2ig ;ct t engine’s hot environment be hotter than ambient temperature. Liquid nitrogen (77 K) is about as cheap as bottled water. What would be the efficiency of an engine that made use of heat transferred from air at roomxdr972vt;ct( cwi egg+ vdp( , 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 whkm)sp)x o-h6wp.-nfj ile using 680 kcal of heatf))p k.j-mh soxw6pn- per 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 temperaturp qn(1nj d.a v-eecnxg54y.j)es 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 exqsi,3dho f bj;x16pr- 8we3MW of electric power. Estimate the heat discharged p;o,sxxd1r 363ebw ih fj-q8peer second, assuming that the plant has an efficiency of 38%.    $MW$

  A heat engine utilizes a hm2hj 9 sab),ll4b.mhieat 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 hee 4o *( pz*10d xqi-77pgt9sro ioqk5 awakeu6at 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 engiid m drb qy688x:zirog6hnx.mc/ 5)9 fnes work in pairs, the output of heat from one being the approximate heat input o:ri. )yhfm6d9qo56xcdgx /rz8b nm i8 f the 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 cool fqp/z r-cxp7q:hi 177crz/uo;die 1xing 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 opzljoeqd5)pb ; 4z+ c6zerates with a in a 24$^{\circ}\,C$ room. What is the temperature inside the freezer?    $K$

  A restaurant refrigerator has a coefficient of performance of 5.0. If the temper, 2/ 7c pt0.uax*dwzpmqwg,tjature in the kitchen outside 7,0z qpawj.,*x2dpt/mcgwut 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 o(la,)p ;98mbplq m-s 4*k 1xmeh vfhmhouse 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 a; onlp4j;pf 5lt 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 p(cv1n ht1 yn8+x 7jdnng6n8 uqossible to run it backward as a heat pump, what would be its coefficient of performxjgnv+ n tqunh(6y cn7 dn8118ance?   

  What is the change in l-8..wqwstj/kb6 ymk 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 ists5ygiw.a2l/wwq 5/ q heated from 0$^{\circ}\,C$ to 100°C. Estimate the change in entropy of the water.    $J/K$

  What is the change in entropyea74 lf-ge(pz jzm5 n0 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 az 4llbudwe5lqurf/of02q7 be7 )r6 / yxw eq39n 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 befor f86;ew jro6kbb. , mt uslca2fq)5tf/e striking the ground and coming to rest. What is tkq /86cf5e6b)l.wa ;mtorf2t,b jsf uhe total change in entropy of the rock plus environment as a result of this collision?

  An aluminum rod conducts +5vd vx9hzqs;+phc m0 $7.50\,cal/s$ 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+3t1r,we k)jpkt)x0eau hs 4i0$^{\circ}\,C$ 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 aluminumgp o0(4biu 2ldw:21e*dcpjhg 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 aypeke;2km sq(q(s r.4nd 650 K produces 550 J of work per cycle for a heat input of 2200 rm4(p skk;(eey2q.qs 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, whe 4d2gxyo8ucakb/k9 j -4 i)bohn 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 increc)used**c*xf+ 5k t)vtmt+ y6 m iet*jasing probability: (a) four aces v )jct*+f 5ki u cxd) st*6e+my**ettmand 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 and macrostates.

  Suppose that you repeatedly shake six coins in your ha dy 7ir4:r93sel s0vafnd and drop them on the floor. Construct a table showing y49ls r 3ar 7:di0efsvthe number of microstates that correspond to each macrostate. What is the probability of obtaining
(a) three heads and three tails,   /64
(b) six heads?   /64

  Solar cells (Fig. 15–261 4q wmilkc19jeip ;,n) can produce about 40 W of electricity per square meter of surface ar ,jk;cniwmp19q ei4 1lea if directly facing 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:b, e4njle6vpdq,k83f k6 pjp demand by pumping water to a high reservoir when demand is low and then releasing it to drive turbines when needed. Suppose water is pumped to , v36k,bnk4ep :jepjqfd 6 lp8a 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 bvy ly75cytrwem, y0 -dy)(q* created by a dam (Fig. 15–27). The water depth is 45 m at the dam, and a steady floy -,mydy*ltqvcry0)b( 7 5 yeww 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.+a-e;/lp fle7b30)cokfp apv 50 MW of usable work while taking in 3. k7-3 vfpfoe;aa0pbcl lpe+/)00 MW of thermal energy 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 a.s8j)lhpy q- lr 6dz3qnd delivers 220 J of work per cycle per cylinder. h .ps jr-z)638dqlqylWhen the engine fires at 45 cycles per second,
(a) what is the work done per second?    $ \times10^{4 }J/s$
(b) What is the total heat input per second from the fuel?    $ \times10^{5 }J/s$
(c) If the energy content of gasoline is 35 MJ per liter, how long does one liter last?    s

  A “Carnot” refrigerator (the reverse of a bcu +/bdf0 +muc .shk8Carnot engine) absorbs heat from the freezer compartment at a temperauukhcdc. 8bs +f /0+bmture 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 co49yqdve)9b9hc(dk:sby7gzed v 1z 4q uld be developed that made use of the temperature difference between water at they hv)q ygzv1(:dde4be9 79qdkb9z4s c surface of 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 directions when they collide lu e.ztk/:y;uand are brought to rest. Estimate the changeku. /zey:; tlu in entropy of the universe as a result of this collision. Assume $T\,=\,20^{\circ}\,C$    $J/K$

  A 120-g insulated aluminum sh) te wn(bi58igw-/wcup 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 extractsi(8dp hq*z k9ya qy2wqq8xfv ;i0)m+m heat from *mqy p 8 ak9w dqfxhiviy)qq 02z8+(m;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 releasez8ip e ) -*zm5p/o,vjyoljw9ls 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 loaj:ick6:p1 eiwer operating 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 og+w9zrp9mto )3 3ig gstate C in Fig. 15–28 for each of the following pro3mgo tgw g99p ir+zo)3cesses: (a) ADC, (b) ABC, and (c) AC directly.

  A 33% efficient power plant puts out 850 MW of electrn)yed nfq w)/a2+,zzvical power. Cooling towers are used to take away the zwq z 2 +))ena,f/vydnexhaust 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 usinnc c-icbs,de99b 1)hgx(y/+ woef o2cg steam turbines. The steam goes into the turbines superhe(f+c9e -9 woh,bsiycx2cen)bo c/d1g ated 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 engine’s wadt7c f9om4.z- eji bd:ter temperature of 84e 7dzf. md:bij9 otc-5$^{\circ}\,C$ 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-sec5dit:g 3t a n2;(hrobjtional 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 o k+)qc+4lwb gha/o:h7 c xdxx)f 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 th),mwa vc/ j09bl 6dv bx1o9: q1tjuqyie temperature inside a room at 21$^{\circ}\,C$ when the outside temperature is 32$^{\circ}\,C$. If 5.3 kW of power enters a room through the windows in the form of direct radiation from the Sun, how much electrical power would be saved if the windows were shaded so that the amount of radiation were reduced to 500 W?    W

  A dehumidifier is essentially a “refrigerator with an open door. ;,deqdon6 1 v;3jknxhdmo d li2o5n02” 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 temperatud;e hl nmi0k62o;d,5o ond3q n1vxdj2re 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