What happens to the internal energy of wa0hnsxuj,u 6le 6 zdr78ter vapor in the air that condenses on the outzjd68r0n7, sxeluhu 6 side of a cold glass of water? Is work done or heat exchanged? Explain.

Use the conservation of energy to explain why the temperature of a gas incrwgre4 /m:5 o dnn/+6kcjqg) oneases wrnqe // wd6on+ 5go)gj cmn4k:hen it is quickly compressed — say, by pushing down on a cylinder — whereas the temperature decreases when the gas expands.

In an isothermal process, 3700 J of work iq- ;hjfnochuvy+9ta(.d)mt;fm q d;, s done by an ideal gas. Is this enough information to tell (-tm,o; jqcqdn yaf.9 mv ;;huth)fd+ how much heat has been added to the system? If so, how much?

Is it possible for the temperature of a system to ry6;f9romrcwpi 1*h az6 ;gp6vemain constant even though herc fmyg;v*9 hp;a1z 6ripw66oat flows into or out of it? If so, give one or two examples.

Explain why the temperature of a gas increases when it is adiabal:-ntkh -z5z ltically compresszz5lhl -tkn:- ed.

Can mechanical energy ever be transformed completely into heat or internal eq q0ze7 ;46uk)ci rrgsnergy? Can t c; g)rseu k4q7izq60rhe reverse happen? In each case, if your answer is no, explain why not; if yes, give one or two examples.

Can you warm a kitchen in winter by leaving nezhb+jlu+c198; m rwthe oven door open? Can you cool the kitchen on a hot summer r;znb 1jwel+mu8h+9c day by leaving the refrigerator door open? Explain.

Would a definition of heat engine effiq*gd,fcq8amq6v u9 sc6 u)qg7 ciency as $e=W/Q_L$ be useful? Explain.

What plays the role of high-temperature and low-temperature areas in (a) a ,eqlmq yi :ksa3 jzs7(i+e19jdcdb4;n internal combustion engine, and (b) a steam enginejmd4;a z7(d ki+ibs :e syj,qc19e3ql?

Which will give the greater improvement in vqpcbzmrrcu6t01x4m 0u4nu)(r bdf 2y 7/ l*vthe efficiency of a Carnot engine, a 10 q74 *rr0)cu2d c1mbnbvx/6v( 0luz yum4trfp$C^{\circ}\,$ increase in the high-temperature reservoir, or a 10 $C^{\circ}\,$ decrease in the low-temperature reservoir? Explain.

The oceans contain a tremendous aa0ajn ua 4j(l8mount of thermal (internal) energy. Why, in general, is it not possible to put thn0a(4ju j8laais energy to useful work?

A gas is allowed to expand (a) adiabatically and (b) isse4vvx knnn08 x-g:*r othermally. In each process, does the entropy increase, decrnxe r g:0nn*v -8k4vxsease, or stay the same? Explain.

A gas can expand to twice its original vo3)g*:- boq **.xb r5yr*giteqioh umglume either adiabatically or isothermally. Which process wty qxqm*bg*o 3*-b.gu )ri*igr:o e 5hould result in a greater change in entropy? Explain.

Give three examples, other tzynrgyny47w w. ;0f/8 vaute*han those mentioned in this Chapter, of naturally occurring processes in which order goes to disorder. Discuss the observability of the reverse procesgz ; a w7wntevr4.08/yy*uyn fs.

Which do you think has the greater entropy, 1 kg of solche 6j mormwf6f +1r8:id iron or 1 kg of liquid iron? Wr fof6+r8:m 61jh cwmehy?

(a) What happens if you reizwtl)st(o(b c .4v8 pmove the lid of a bottle containing chlorine gas? (b) Does the reverse process ever happen? Why or why noltc (bvo z.4i)8wpt(st? (c) Can you think of two other examples of irreversibility?

You are asked to test a machine that the inventor calls an “in-rool x8/jz: bt)/ l 7hdk 35azuymzbica+5m air conditioner”: a big box, standing in the middle of the room, with a cable that plugs into a power outlet. When the machine is switched on, you feel a stream of cold air coming out ycb 7luz )mkzz5lj:i5/xa3 d/t a+8bhof it. How do you know that this machine cannot cool the room?

Think up several processes (other than those allcauj4z7k i*;t8onu0ready mentioned) that would obey 48alz*0it;j ok un7u cthe first law of thermodynamics, but, if they actually occurred, would violate the second law.

Suppose a lot of papers are strewn all over the floor; then you stack them o0iwe qmtpzb/ 9u l2 h:0z))qrneatly. Does this violate the secon9t )rbz0ml/oq )q2hi0ew :zupd law of thermodynamics? Explain.

The first law of thermodynamics is sometimes whimsically stated afk)-6 *ej gobvn,qir4s, “You can’t get something for nothing,” a,nq6 joeb4 k*igf-)r vnd 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 “time’s arrow” because it tells us in dy .a )6*wmiejj.o;hroi-mt4a8 wu -lwhich direction natural processes occur. If a movie were run backward, name some processes that you might see that would tell you that time w)jhuawo4d8j*iayr lo-i ; m-tm 6 ..ewas “running backward.”

Living organisms, as they grow, *obnglpb-a ;1y4ro6q convert relatively simple food molecules into a complex structure. Is this a violation of the second law of the*ao p61b4q-ogn ;r lybrmodynamics?

  An ideal gas expands ishmd k*fa.m+.r4t co1c othermally, 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 a light frictionless pi(u- qi5i9 hr pfd,nwj:ston and maintained at atmospheric pressure. When 1400 kcal of heat is added to the qjdf- uin,w i(:p5hr9gas, 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 atyxi9c r i.aqf.44vdw/ constant pressure until its volume is halved, and then it is fa r 9c.qxw4i/iy.dv4allowed to expand isothermally back to its original volume. Draw the process on a PV diagram.

Sketch a PV diagram of the following process-bdlzwu5b- n, : 2.0 L of ideal gas at atmospheric pressure are cooled at constant pressure to a volum5ub,lw- nzbd -e 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 i;3 zpxea be;i:nitially 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 process on a PV diagram, izp3 ; ;eexa:bincluding numbers and labels for the axes.

  The pressure in an ideal gas -dewadnul kp3n 8 k2sivhs 5:z u+(x55is cut in half slowly, while being kept in a container with rigid walls. ad:wud5 nple(k2-s nz3 55h si+xk vu8In the process, 265 kJ of heat left the gas.
(a) How much work was done during this process?    $J$
(b) What was the change in internal energy of the gas during this process?    $kJ$

  In an engine, an almost ideal gas is compress1 /frp+ td:vph2y- bsred adiabatically to half its volume. In doing so, 1850 J of work is donep2b-pytr 1 v+s:rh df/ 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 pressure yd04o-/ag-jlzzq2m z of 3.0 atm from 400 mL to 660 mL. Heat then flows out of the gas at constant volume, and the pressy m lad4/z2gz--0ojqz ure and temperature are allowed to drop until the temperature reaches its original value. Calculate
(a) the total work done by the gas in the process,   $J$
(b) the total heat flow into the gas.    $J$

  One and one-half moles of an 3id 8d,hgl8 s2y9 ibnxideal monatomic gas expand adiabatically, performing 8hi sdn,iyb29 dx83lg 7500 J of work in the process. What is the change in temperature of the gas during this expansion?   $ K$

  Consider the following two-step process. Heat is allowed to flow out of a+zpde6d -h+,u7l78z ne 7tmm hsjmr u,n 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 original value. Se s+,7uj hm+m-7ln7du rdezt ,m h8pze6e Fig. 15–22. Calculate
(a) the total work done by the gas in the process,    $J$
(b) the change in internal energy of the gas in the process,    $J$
(c) the total heat flow into or out of the gas.    $J$  ----待选择----intoout  the gas

  The PV diagram in Fig. 15–23 shows two possible states of a system contain7l 8d*kdxgn*oing 1.35 moles of a monatomic ideal gasdkx*dg8o7 l* n.$(P_1\,=\,P_2\,=\,455N/m^2,V_1\,=\,2.00m^3,V_2\,=\,8.00m^3)$
(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, d8bg 0sl -v+pxthe work don dl-0v+8sbx gpe 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 d0, -i bn1w.pn*mnzw efrom state a to state c along the curved path shown in Fig. 15–24, 80 J of heat leaves the system and 55 J of work is done on the sy w1*nnedm zpn0 i,.-wbstem.
(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 ifpuizf2v8( l w2 instead of working 11.0 h she took a noontime break and ran z(2l vi2 u8pwffor 1.0 h?    $ \times10^{ 7}J$

  Calculate the average metabolic rate of a person who sl2xt1s)sje( nlhm 3t)*v jz*+ 6mnah fueeps 8.0 h, sits at a desk 8.0 h, engages in light activity 4.0 h, watches htzmlsmfxev a21 t3 hj+jn(n* 6*s) )utelevision 2.0 h, plays tennis 1.5 h, and runs 0.5 h daily.    $W$

  A person decides to lose weight by sleeping one hour less per d1ldgfa x:2yawlac80byb5*1f ay, using the time for light activity. How mu l5ab1fdw y: clx*agyfa2180b ch 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 energy.   kg(retain one decimal places)    $lbs$

  A heat engine exhausts 8200 J of heat while performing 3200f))b5 x3xwzv17mqk rm J of useful work. Whf15z)mm xxr kvwq 3)7bat is the efficiency of this engine?    %

  A heat engine does 9200 J of work per cycle while absorb qpim 4x ouw+(-5em+liing 22.0 kcal of heat from a high-temperature reservoir. What is the efficiency of this engi5 po+ m(ixql-4eu+miwne?    %

  What is the maximum efficiency of a heat engine whos o8((loog*c pme operating temperatures are 58cmogp( (o8 o*l0$^{\circ}\,C$ and 380$^{\circ}\,C$?   %

  The exhaust temperatu3j 8:el wq)jajt dnq3qo*x/z .re 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 e8jdni-1,o4gq) zk u pmaximum theoretical (Carnot) efficiency betwnoz-pe4 u,kj1)8 ig qdeen 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 hex07eg yx4t4fgijm;p7z eh7d q2x4(ap at engine’s hot environment be hotter than ambient temperature. Liquid nitrogen (77 K) is about as cheap as bo (07fi2zphqg4 4 ;4jaexpxmyt7dg x7e ttled 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 z-wfgcb3d; b6rate of 440 kW while using 680 kcal of heat per second. If the temper-3bcgd ;bwf6z ature of the heat source is 570$^{\circ}\,C$, at what temperature is the waste heat exhausted?    $^{\circ}\,C$

  A Carnot engine’s op 6dmi5m(rra2verating 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 MW of electric power. Estimate the hc d k.gr)5o3)ja*tu kbeat discharged per second, akk 3uta)db)5j.*rcog ssuming that the plant has an efficiency of 38%.    $MW$

  A heat engine utilizes a heat xm21xio1+y cpsource 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 hqgwwb9v 76qjgyf3. .peat 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 plantbi 9c*fksbx,7d9cl.m0 t:,fssa g k-m, steam engines work in pairs, the output of heat from one being the apflm 9a9, k:*gibfsdxk t0 s 7bcm.,-scproximate heat input of 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 coolii j9x7zrp)o0 kng 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 operp wrru3t2)nwe0j j;n kjn 8z5.ates 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 tyxuqh xu(+x; b1+ f+xjhe temperature in the kitchen outside ux ;b(1f jx+yqx+ x+uhthe 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 djlgul.f+7 v6 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 2 yet8gshe16rxn6k( ib 5u:akat 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 possf-owb3w6iu k.z 5m)rlible to run it backward as a heat pump, what would be its coefl wfwkimouzr5-3b6 ) .ficient of performance?   

  What is the change in entropy ofr-;:1f+ n-v fj d:2pj 8oa7v xzfpciwd 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 cz . ;kx:lar*fheated from 0$^{\circ}\,C$ to 100°C. Estimate the change in entropy of the water.    $J/K$

  What is the change i i)i0-xvvan9 4iy o, q*nulg 9+6cjhwqn 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 c,o;sjijz95x 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 before striking the ground an-h;tp o,(syssc tsb ;:d coming to rest. What is y;(tsts: p- h ,ssb;cothe total change in entropy of the rock plus environment as a result of this collision?

  An aluminum rod conductalbvxzig 55)o,unc k( :bg1( ds $7.50\,cal/s$ 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 3nkpie1b pp0:3ml(bmu .b )3a l0$^{\circ}\,C$ 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 ,me;:yjkl u /b30$^{\circ}\,C$ 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 6ww,ice;4m/b7e6e n- erf5f sz50 K produces 550 J of work per cycle for a heat inputr n,4m 5 -fee7icwew6 efzsb;/ 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 obk*8i gfrwuvc / *g7c;ytaining
(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 probabi7h k vj5cvxpc5/6 ;mtglity: (a) four aces acx/ 5pmjg 6hv7kt5; cvnd 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 hand and drop them on the flaysu +9d :s ai0zfh16ooor. Construct a table showing the number of microstates that correspond to each macrostate. Wha+isy :91sf0hau oa6zd t 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 electricitv 8psj 54 9:2dn5+qjrsbch thry per square meter of surface area if directly facing the Sun. How large an areatcj pv5 :4h2h59rrjs8+nqbsd is required to supply the needs of a house that requires $22k\,Wh/day$ Would this fit on the roof of an average house? (Assume the Sun shines about $9h/day$)   $m^2$

  Energy may be stored for use during peak demand by pukq1dif w :bz1y,g)hvu4d,j0 ymping water to a high reser jy )g0 dy1uq iw:,,1hvfzkb4dvoir when demand is low and 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). Th78+hbyyhk:k in0z3 nne water depth is 45 m at t:b ni8k3hyzn7k0 +hynhe 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 havdb9mh96ev p+xe designed and built an engine that produces 1.50 MW of usable work while taking in 3.00 MW of thermal energy at 425 K, and pbmexh6 +9vd9 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 05e3a.rm2o zvuxer iyep( 4 r d25qi(6g.25 and delivers 220 J of work per cycle per cylinder. When the engine fires at 45 cycles per .(5e uamx2qrg(i3y 5peovzi4r 62rd e 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) absor6:coxf 0z qcq0yl.k4nbs heat from the freezer compartment at a tempen6qcozq04cyx 0f: l .krature of -17$^{\circ}\,C$ and exhausts it into the room at 25$^{\circ}\,C$.
(a) How much work must be done by the refrigerator to change 0.50 kg of water at 25$^{\circ}\,C$ into ice at -17$^{\circ}\,C$    $ \times10^{4 }J$
(b) If the compressor output is 210 W, what minimum time is needed to accomplish this?    s

  It has been suggested that a heat engine could be developed that m7ub+oixm); 1kdy q/ec ade use of the temperature difference between water at the surface of the ocean and that several hundi /e+ck db1y7);uxqmored 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 oppositeo .z4q*e3fv lrfv6ljfk6 qu1wfk)m4* directions when they collide and are brought to rest. Estimate the chaw. ufkvlk 1f)vq *6jff r4*m3eq4o6lznge in entropy of the universe as a result of this collision. Assume $T\,=\,20^{\circ}\,C$    $J/K$

  A 120-g insulated aluminum cupdwnk()kir0u. tnfmsq: w 3y)5w6dk2:,ae esw 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 ext5f)bv,ajfwy98 piv5m 4/cak p racts he 4ji f8mpv5 ,ky/pvwc 5a9afb)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 gasol p*qm6wc6v kxmqu5+ife0fq 82 ine in 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 operatin hud1ih;((y5 oejk, mbjcm7t4g 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 from7sqv 1tjgly11h/oi5 e state A to state C in Fig. 15–28 for each of the following processev lg/i1o1j7q y t1she5s: (a) ADC, (b) ABC, and (c) AC directly.

  A 33% efficient power plant puts out 850 MW of electrical power. Coo)jv*2;xup8vy dfl5 a wwc 2fl4ling towers are used to take away the exh fl 24wjuy*xa2cwp 5lvvd;f8) aust 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 q20k,i+w:t c ycy1bfo: l/txgwycj: 7ing steam turbines. The steam goes into the turbines superheated at 625 K and deposits its unused 1qyit wc7:+f:/cw ,y:bk tgcolyxj20heat 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 fv1vsh07l:94 rwxw psj)o:a5dq k *v aat about 15% efficiency. Assume the engine’s water temperao:4095pa7*vjf)kqv1asrx dw lwh:vsture 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 placed in a tall cylindrical jar of crosshx7 +y8unyj 2dq82fpm-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 fat6jo f k8)2ippc 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 roob 9yaa0km35:l sbnqm .m 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 “refrigetehau+d(k-, e 0lp62xjnu 6aa)l3 x harator with an open door.” The humid air is pulled in by a fan and guided to a coln (apd,ku+hl-ju60)eah6 laxxe3 2a td coil, where the temperature is less than the dew point, and some of the air’s water condenses. After this water is extracted, the air is warmed back to its original temperature and sent into the room. In a well-designed dehumidifier, the heat is exchanged between the incoming and outgoing air. This way the heat that is removed by the refrigerator coil mostly comes from the condensation of water vapor to liquid. Estimate how much water is removed in 1.0 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