What happens to the internal energy of water vapor in the air that condevtmia; jmj *(9*.dyfunses on the outsidy.ma v(9*d*; imjtujfe of a cold glass of water? Is work done or heat exchanged? Explain.

Use the conservation of energy to explain s3vva;pwq8t y; 5e /yk: jvfboxy.,g;why the temperature of a gas increases when it is quickly compressed — say, by pus5 vko.ja/spw : ytyf8q3;yx g v,;bve;hing down on a cylinder — whereas the temperature decreases when the gas expands.

In an isothermal process, 3700 J oo0z*z:buy tgm6 d g5t;f work is done by an ideal gas. Is this enough information to tell how much heattm* 5;yzd:0bugzg6 o t has been added to the system? If so, how much?

Is it possible for the temperature of a system to remain co7l +nccgwvl,q23 m ww9 nnvt1.nstant even though heat flows into or out of it? If so, give one or two exampll1v2lwt 3+q.9n,cn w v7cwgmnes.

Explain why the temperature pyh1(sj th3h; of a gas increases when it is adiabatically compressed3tpjhsy h (1h;.

Can mechanical energy ever be transformed completely int4 :7eifwo+ ixrul:2a fsobjjej0 j :)*o heat or internal energy? Can th+i0rej:eo : f :abjfi7*4jws)x uol 2je reverse happen? In each case, if your answer is no, explain why not; if yes, give one or two examples.

Can you warm a kitchen1td9eox4zj/(a y5a -zzez9jy in winter by leaving the oven door open? Can you cool the kitchen on a htyzd ( ez4ajzy5/ 9jeaox19z-ot summer day by leaving the refrigerator door open? Explain.

Would a definition of heat engine efficiency as wm d5d9 4p aq)1wmpw/x9lvrew:rq.5 i$e=W/Q_L$ be useful? Explain.

What plays the role of high-temperature and 5s40 bpac*8iy(q rfqy low-temperature areas in (a) an internal combustion engine, and (b) a steam(q cf*sp8r4qay50biy engine?

Which will give the greater improvement in thezzql/5-hk23e s(-bdesz cmt q+7lc;)hy .osk efficiency of a Carnot engine, a 10 so. e 2sz-l t+e;(yhqdcm75lkb3 hc q)sz-/z k$C^{\circ}\,$ 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, in geeyuuouw8.d+j. 9v 7x( yc5k vzin w8d.neral, is it not possible to put this energy to useful wor uzk i(d.c7e5vnw.xwyy j+8vd89u .ouk?

A gas is allowed to expand (a) adiabatically and (b) isothermally. In each p2ovrl6 fh9qxxmg,d1hr) 0dtu m l-2v1rocess, does the entropy increase, decrease, or stay the same? Explain., u r2mmfhx-2ltg rv)oxqd1dh9016lv

A gas can expand to twice its originalp,wh61 u+s*lj-s6b lbtbpi+l volume either adiabatically or isothermally. Which process+hwlis1bb*u 6pl+pb sj6t,l- would result in a greater change in entropy? Explain.

Give three examples, other than those mentioned in t6 c 8)9khpowethis Chapter, of naturally occurring ptcw8) k eho96processes 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 kg of liq/9 ly qae+ab3suidab/aq3sye l9+ iron? Why?

(a) What happens if you rem23suv-z nkw: ep: 3nvrove the lid of a bottle containing chlorine gas? (b) Does the reverse prz: rn- s:3n2v3up kewvocess 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 c8broe mk 1*yk9alls an “in-room air conditioner”: a big box, standing in the mi*9yebr1 mok8 kddle 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 a8o-+gko6dg p wy+:a*ms.ek5n;f cq pulready mentioned) that would obey the first law of thermodynamics, but, ifp; 5fsodnq6-k .yg8ku cp:o+a w+*gm e they actually occurred, would violate the second law.

Suppose a lot of papers are strewn all over the floor; then you stack themjmw5i kgc* f6, h22mgs neatly. Does this violate the second law of thermodynamics? Explain,2mgimfcw *ks6 5 hgj2.

The first law of thermodynamics is sometimes whimsicall;s9rxyzc7rxz3 9nigl0e(r:gwua4 s * y stated as, “You can’t get something for nothing,” and the second law as, “You can’t even break even.” Explain how these statements could be equivalent to theas y;0zrr u 7cr4sx* ngz3xl9gi (:w9e formal statements.

Entropy is often called “time’s arrow” because it telljmwcm6 ;* 4 tbsgqqi3yq/8yq(s us in which direction natural processes occur. If a movie were run backward, name some processes that you might see that would telsjqw b8 /mic*3y gm4;(qqq6 ytl you that time was “running backward.”

Living organisms, as they grow, c uqe5q+ pdqn5(onvert relatively simple food molecules into a complex s5qqnp( dq5u +etructure. Is this a violation of the second law of thermodynamics?

  An ideal gas expands isothermally, performing 8dc.l01hcob ldd e80uc/ kfk3$ 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 4o0 we 5i53*spd3l 6jo xaxosdfrictionless piston and maintained at atmospheric pressure. When 1400 kcal of heat is added to the gas, the volume is observed to increase sl0ido4xpl5a sd 5oo6 3e*x j3swowly 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 unt ,wc3uc1g8ncuil its volume is halved, and then it is allowed to expand isothermally back to its original volume. Draw 1cgu8wn ,cc u3the process on a PV diagram.

Sketch a PV diagram of the fol6:8ecs ttde7mpjh u -,lowing process: 2.0 L of 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 pt pems,ct-:u8 6hjed7ressure is reached.

A 1.0-L volume of air initially at 4.5 atm of (absolute)//dgc x3eq fno8t-a b2 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 theg x/ d8 -eqbtcfna2o3/ process on a PV diagram, including numbers and labels for the axes.

  The pressure in an ideal gas is cut in half slowly, while bvu vza+ z+y56ieing kept in a container with rigid walls. In the process, 265 kJ of heat le+ay u6 izv+vz5ft 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 almosr(a ,rpb t4vgu 4vi(;k0wv;cxt ideal gas is compressed adiabatically to half its volume. In doing so, 1850 J of work is done on the gas. ;v4 uc;w,bt(rxrv av0 k4(ipg
(a) How much heat flows into or out of the gas?    $J$
(b) What is the change in internal energy of the gas?    $J$
(c) Does its temperature rise or fall? ----待选择----fallrise 

  An ideal gas expands at a constant total pressure of 3.0 atm from 400 mL to 660 gotga58 tw h4v:3 t:remL. Heat then flows out of the gas at constant volume, and the pressure and temperature are allowed to drop untg:gt e to5v:48 wtha3ril 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 adiabaticallj3js jcoli4 q; ,q4u2ky, performing 7500 J of work in the process. What is the 4 4jqu3 qj2jcksi,; lochange in temperature of the gas during this expansion?   $ K$

  Consider the following tswikn(c 8l0 b,tzc.k4 wo-step process. Heat is allowed to flow out of an ideal gasst.80cnzcik lb, (k4w 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 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 Figa6dwnjz4/s v ;. 15–23 shows two possible states of a system containing 1.35 moles of a monavz ;w6adj4n /stomic 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 alo zxv dw+/1kqipz0) :gwbq1v +lng the curved path in Fig. 15–24, the work done by the gab/qxzq + kvwp zg0d1vw l+)1i:s 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 thepu7wt;6 +rkbx curved path shown in Fig. 15–24, 80 J of heat leaves the system and 55 Ju;w k7p6b+rxt 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 Exab9xm e;+as 7u,nfbf m+lc wh.*mple 15–8 transform if instead of working 11.0 h she took a noo+ cuh9.mmawsb7 xf+;e,n* bl fntime break and ran for 1.0 h?    $ \times10^{ 7}J$

  Calculate the average metabolic rate of a person who sleeps 8.0 h, sits at a4w.(n1ah/ywiv rn b 4f *mq(ei desk 8.0 h, engages in light activity 4.0 h, watches televin yrq1ww.h /4n m4vb af*(i(iesion 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 qfc* sst0dx-7+ci)xrn)l ) hiless 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 o+ sl cx) d0t*fc)siqn x7)ri-hf energy.   kg(retain one decimal places)    $lbs$

  A heat engine exhausts 8200 J of heat while performing 32038wdu5qmy-3 3l hlukr0 J of useful work. What is the efficiency yuq-3 ulwrd5m383 hlkof this engine?    %

  A heat engine does 9200 J of work per cycle while absv +o b,ra ijz )kvh2+zi2t:x.dorbing 22.0 kcal of heat from a high-temperature.axdv+ riz jb+z t,o2):k2hvi reservoir. What is the efficiency of this engine?    %

  What is the maximum efficiency of a heat engine wh-xaro cj bk9gvo- f .06;j6lqdose operating temperatures are-fj-k6ag; vd qrojx6.90 ocbl 580$^{\circ}\,C$ and 380$^{\circ}\,C$?   %

  The exhaust temperature of a yfs9i5 +c q4 5nslwpt5heat 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 (Carnot) edqvdpk 9b4iu;u0 y5 9tfficiency betwee;bu5v9yu k0q9p dt 4idn 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 that a heat engine’s hot environment be hvp5-ap ofil05l0yy*3nu (zjw otter than ambient temperature. Liquid nitrogen (77 K) is about as cheap as bottled water. What would be the eff(-zy5fwynp*30 0l l opv iuj5aiciency 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 performs5,y 3qqgprun f+yd.v 9ny)w /vybvj c, z:vh47 work at the rate of 440 kW while using 680 kcal of heat per second. If the temperature of the heat sourcyp, g5w)+y,4n vq3rh v f.vc yzvjy bqnu:7/9de is 570$^{\circ}\,C$, at what temperature is the waste heat exhausted?    $^{\circ}\,C$

  A Carnot engine’s operating tem nrh6*-kf.t ul/ +mcuyperatures 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 elkg8arffymiql0f7 ;3(ectric power. Estimate the heat discharged pery rgl( ff a0fm8qk73i; second, assuming that the plant has an efficiency of 38%.    $MW$

  A heat engine utilizes a heat0 8xg t/d)hcuns cc.8v 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 exhausqbxgo z73o ew*4ww14 qts 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 pairs,*q3sju ,up k:32xr 3 f;uuakgy the output of heat from one being the approximate heat input of the second. The operating temperatures of the fi2kj3 u:xua33qu ug,fr*pk sy;rst 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 ; (+svom /pztdcooling 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 ekp20hx2sh0;o nltumm5, ; jda 24$^{\circ}\,C$ room. What is the temperature inside the freezer?    $K$

  A restaurant refrigerator has a coefficient of performance of 5.0. I8frg uq(3zat+f the temperature in the kitchen outside the refz8 q(+tfa3gurrigerator 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 t *f,jq xvgl+y9pe r9:ko keep a house warm at 22$^{\circ}\,C$. How much work is required of the pump to deliver 2800 J of heat into the house if the outdoor temperature is
(a) 0$^{\circ}\,C$,    $J$
(b) -15$^{\circ}\,C$ Assume ideal (Carnot) behavior.    $J$

  What volume of water vb,s)(okgt e2 at 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 w8hqpan 4s*/l-yxuq 1efficiency of 35%. If it were possible to run it backward as a heat pump, what woul 8wql-sh qnp*uyx1 a/4d be its coefficient of performance?   

  What is the change in entropy ruxqz z,m* xnpc60:t 2q(7ziy 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 heatef y)tg12z3lyt d from 0$^{\circ}\,C$ to 100°C. Estimate the change in entropy of the water.    $J/K$

  What is the change in eain xfbiz(7ov3x0(/hntropy 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 inith oj + h.xxn+ ,ic*ze.2.hhswk(--zjrxqso8x ial 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 before striking to iw; ;th. *s gcd/bgj*r8y+qqhe ground and coming to rest. What is the total change in entropy of the rock plus environment as a result of thh; .w;bostqicqgdj g+r/y*8*is collision?

  An aluminum rod conduc zw,izd qj)j *7xq4sdwm:-d9vts $7.50\,cal/s$ 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 3xrsfzfxqr *f ia-7 z6m:27h6h 0$^{\circ}\,C$ 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 alumimr13 - oeqt2cnnum 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 reb53te4l6uj lk servoirs at 970 K and 650 K produces 550 J of work per cycle for a heat input of 2l4 u l6kbt5e3j200 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+cwyo9 ec7urr2vm uko -f d:5+ 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 fiv3 ohp7yb veqo s-s4s.,e-card hands in order of increasing probability: (a) four ac ,sbepy-.s q3h7oov4ses 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 and macrostates.

  Suppose that you repeatedly shake six ety;.ux) u -pmcoins in your 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 )yt e.p;u-u mxobtaining
(a) three heads and three tails,   /64
(b) six heads?   /64

  Solar cells (Fig. 15–26) can produce about 40 W of e o;vm5 rnhxcx,r,4 3ctr6 p7wolectricity per square meter of surface area if directly facing the Sun. How large an area is required to supply the needs of a house thacnr36xhor; ,rctwo xv47pm5,t 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 hig3i bu37ywf9drh reservoir when demand is low and then 9wb7r3 uidf3 yreleasing 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 ahlc q8n/;g6 ogn artificial lake created by a dam (Fig. 15–27). The water depth is 45 m at the dam, and a st chg 8qn/ol;6geady 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 :pmtjy w6a pcf1a3if3k ,u5- lengine that produces 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. I lpua6 jftp1:k5fac3m3y wi-,s 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 engix f;*(tubgs m.emkxa1y7 b3i* ne has an efficiency of 0.25 and delivers 220 J of work per cycle per cylinder. When the eng1x*fibs7 *xbke(u. t a mmg;y3ine fires at 45 cycles per second,
(a) what is the work done per second?    $ \times10^{4 }J/s$
(b) What is the total heat input per second from the fuel?    $ \times10^{5 }J/s$
(c) If the energy content of gasoline is 35 MJ per liter, how long does one liter last?    s

  A “Carnot” refrigerator (the reverse of a Carnot engine) absorbs heat from +*xbt(*w /wwto v qgnd9r:sw. the freezer compartmentwsd b/t 9*g(xwww r*v:o.q+nt at a temperature of -17$^{\circ}\,C$ and exhausts it into the room at 25$^{\circ}\,C$.
(a) How much work must be done by the refrigerator to change 0.50 kg of water at 25$^{\circ}\,C$ into ice at -17$^{\circ}\,C$    $ \times10^{4 }J$
(b) If the compressor output is 210 W, what minimum time is needed to accomplish this?    s

  It has been suggested tj .2 ydyv4vk/chpq5b-)o2r n that a heat engine could be developed that made use of the temperature differ)kh-q .oy2 jby4c25p nrvvtd/ence between water at the 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 isqz-msn +(n.dn opposite directions when they collide and are brought ts(m -nsn+q.z do rest. Estimate the change in entropy of the universe as a result of this collision. Assume $T\,=\,20^{\circ}\,C$    $J/K$

  A 120-g insulated alusz9sh yc1v ,* e9tml no..g kutw*r++wminum cup 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 - knc98nxr84gjc0t ylheat pump that extracts he948 -cclkg0jrtyx nn8 at from 6$^{\circ}\,C$ air outside and deposits heat inside your house at 24$^{\circ}\,C$?   
(b) If this heat pump operates on 1200 W of electrical power, what is the maximum heat it can deliver into your house each hour?    $ \times10^{ 7}J$

  The burning of gasoline in a car releases sas,xm mhxdus-6;d33eacf5mz av + 7 3about $ 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 ilc 5y;v yhx 9d en(1bxr1u+6ha lower 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 s 8q,x sszxj5k.tate A to state C in Fig. 15–285z 8x,ksj.sq x for each of the following processes: (a) ADC, (b) ABC, and (c) AC directly.

  A 33% efficient powerh,gki** j mp;t. jyd1x plant puts out 850 MW of electrical power. Cooling towers are used to.p y itmj *dx1j*g,k;h 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 us+ne:lfnh.v tsrs l *3.0fql ;jing steam turbines. The steam goes into the turbines superheated at 625 K and depo; fjnls:q lv*t+3e.lnf.r0hssits 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 d u:u8hf2 s5( 54ghfepncfog6engine’s water temperature of 2eg5o6:hds f8u4hc5ngfu( fp 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 ta*4mx,b))-6qmp gm x:zlivzsl ll 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 fav n)ve9i5 iq9yt 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 atzvavg12jh*j;* , u6dn uvyy7k 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 humia-nr8*psc (red 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 vap (rr8nae*p-c sor 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