What happens to the work done when a jar of orange juz qe8*y ze lbfcevx 21q 6;t.c8sny:g2ice is vigorously shaken?

When a hot object warms a cooler obje/bw/k xyk1 n hrsmzj v*485;mgjf4ys2ct, does temperature flow between them? Are the temperature changes of the two objects equal1w 5ks8yr2bjz jmm fv h/4ks*/;xgn4y?

(a) If two objects of different temperatures are placeddx k.dql ,zpc0;8)hmd in contact, will heat naturally flow from the object with higher internal energy to the object with lower internal energy? (b) Is it possible for heat to flowpm,)z.dkh dq ; 08xdlc even if the internal energies of the two objects are the same? Explain.

In warm regions where tropical plants grow but t;bsv. 10yg6kge)oo+i gk2g kxhe temperature may drop below freezing a few times in the winter, the destructiig2g b; 0g.+)6ykox e1kovkgson of sensitive plants due to freezing can be reduced by watering them in the evening. Explain.

The specific heat of water is quite large. Explain why this f. rkxc z.h9to8act makes water particularly good for heating systems (that is, hot-water .8 to9rkchz.x radiators).

Why does water in a metal canteen stay cooler if the ci+v6e)d+9h vra or mfur20-(yn p yrj2loth jacket surrounding the canteen is keppnr+hu2m ( va9yer )6fory2r 0j +i-vdt moist?

Explain why burns caused by steam on the skin are often more severe thp 4jvrzt(25 vian burns caused by water 5v j2tz(rpiv4at 100 $^{\circ} C$ .

Explain why water cools (its temperature drops) 2a41acbp pxp, when it evaporates, using the concepts of latent heat and internal enpp, c1aa bp24xergy.

Will potatoes cook fcbqv44g:v uv : c qn.6m*j2siyaster if the water is boiling faster?

Does an ordinary electric fan cool the air? Why or whk:u7ly * stcd+y not? If not, why use it?

Very high in the Earth’s atmosphere, the temperat 5jgu/zymkjs1dky*; /- jn*ukure can be 700 $^{\circ} C$ . Yet an animal there would freeze to death rather than roast. Explain.

Explorers on failed i9go9(egjn3dns8q 3dArctic expeditions have survived by covering themselves with snow. Why would they do thg s 3ng9jedi3n8q 9od(at?

Why is wet sand at the beach cooler tor,zi ; g 3-pedzqop+r. walk on than dry sand?

If you hear that an object has “high heat content,” does that mean . m9sfp+ahi5 pthat its temperature is hf+95ma psp. ihigh? Explain.

When hot-air furnaces are used to heat a house, why is it important thi4tc5x(g+sjbrmq yz1t;w2 v 50u+vjr at there be a vent for air to return to the furnace? What happens if this vent i vyj0+ri ruq2 ;5tcg45j svmb( 1w+ztxs blocked by a bookcase?

Ceiling fans are sometimes reversible, so that they drive tv-/z iibs6((u98 a /nxb hweopveh/g9he air down in one season and pull it up in anot(ei6 /a8 g //b9eoszp-9iw b xhuvn(hvher season. Which way should you set the fan for summer? For winter?

Down sleeping bags and parkas are often specified as so maeoolxiu.1p;ghrz+: 7 tl44le ) sa-xcny inches or centimeters of loft, the actual thickness of the garment p4+t hz)1 iecoelx:sogx ;l aur-l4.7 when it is fluffed up. Explain.

Microprocessor chips have a “heat 8glz0ltd8gzn8liz(+m +8tj tsink” glued on top that looks like a series of fizlm88gzndigllj t z0+ 8 t(+8tns. Why is it shaped like that?

Sea breezes are often encountered on sunny da( 2:dxxe6o d4*k pgdmiys at the shore of a large body of water. E(mg2: * 4kpxddxdi6e oxplain in light of the fact that the temperature of the land rises more rapidly than that of the nearby water.

The floor of a house on a foundation under which/pq jfyq, zuyuv8cbnik3m 8jp39-a8. the air can flow is often cooler than a floor that rests directly on the ground (such as a concrete slab foundation). Expln,p .pyiq883jmz9 kcafy bu8v/3juq - ain.

A 22 $^{\circ} C$ day is warm, while a swimming pool at $22\; ^{\circ}C$ feels cool. Why?

Explain why air tempearx*90f+:h5xs78mn z3dcuoqt-a rx q rature readings are always taken with the thermometer in the sh r+5szmdha9r83 aox tx n:-*qu cf70qxade.

A premature baby in an l6vo2ik g/k(. ngh6sjincubator can be dangerously cooled even when the air temperature gjk(6l g6/h2 k.vosinin the incubator is warm. Explain.

Why is the liner of a thermos bottle silvered (Fig.ai *bk8 an/1e 3eelv4m-+rahj 14–15), and why does it have a vacuum betwe8 lva ik *-+mr1enhea4ba/e3jen its two walls?

Imagine you have a wall that is very well insulated —b )7 pw1fimfh /i3dh1g it has a very high thermal resi)71/idhi m f3 p1hbgfwstance, $R_1$ Now you place a window in the wall that has a relatively low R-value, $R_2$ What has happened to the overall R-value of the wall plus window, compared to $R_1$ and $R_2$ [Hint: The temperature difference across the wall is still the same everywhere.]

Heat loss occurs through windows by the following processes: (1) ventilation ar3wx2ec w573lvowt xr 9ound edges; (2) through the frt ww7r xx co5l93e23wvame, particularly if it is metal; (3) through the glass panes; and (4) radiation. (a) For the first three, what is (are) the mechanism(s): conduction, convection, or radiation? (b) Heavy curtains reduce which of these heat losses? Explain in detail.

A piece of wood lying(bu3e l l3 s2)ir/o k:ukqde.h in the Sun absorbs more heat than a piece of shiny metal. Yet the wood feels less hot than the metal when you pick it up. Explainorus l(dlkb /hk. e:23)qi3u e.

The Earth cools off at nigh0lf 9v6.ujmx.i)aa qp)bmt 2tt much more quickly when the weather is clear than when clujp aq 6v)9x)20.aibt t.fl mmoudy. Why?

An “emergency blanket” is a thin shiny (metal coaev8 3,bz6ed snted) plastic foil. Explain how it6envz8e3b ,s d can help to keep an immobile person warm.

Explain why cities situated by the ocean tend to h,;e 1sp.a (vvpgbkll-ave less extreme temperatures than inlan l; e -(,gbakpvpl.s1vd cities at the same latitude.

  How much heat (in joules) is required to raism64weq)b hc2y +.ho nxk/+gaee the temperature of 30.0 kg of water from 15 eg4nk/++yb aqo . wchm62)he x$^{\circ} C$ to 95 $^{\circ} C$ ?    $ \times10^{7 }\,J$

  To what temperature wihbbwv8l ,ci.fyl8w)a,:mtj 2qt(5byll 7700 J of heat raise 3.0 kg of water that is initially at 1v y8 abbl,th5c8,)wwibjqmy l :(ft.20.0 $^{\circ} C$ ?    $^{\circ} C$

  An average active person c .ef*whwxhnk,v xn8a.cd80q ;onsumes about 2500 Cal a day.
(a) What is this in joules?   $ \times10^{7 }\,J$
(b) What is this in kilowatt-hours?    kWh
(c) Your power company charges about a dime per kilowatt-hour. How much would your energy cost per day if you bought it from the power company? Could you feed yourself on this much money per day?    dollars per day

A British thermal unit (Btu) is 6-k;hsu- wxx fa unit of heat in the British system of units. One Btu is defined as the x-wk ;uhsx6 -fheat needed to raise 1 lb of water by 1 F $^{\circ} $ . Show that
1Btu = 0.252kcal=1055J

  A water heater can gen *wexr 0-mwvk*erate $32,000\,kJ/h$ How much water can it heat from 15 $^{\circ} C$ to 50 $^{\circ} C$ per hour?    kg/h

  A small immersion heatbl, 2thulc 8.j. m0pater is rated at 350 W. Estimate how long it will take to heat a cup of soup (ass20cal, p tbhtl j.8.muume this is 250 mL of water) from 20$^{\circ} C$ to 60$^{\circ} C$ .    min

  How many kilocaloriesz0 s.22ag0doiz6peq r-5c ghs are generated when the brakes are used to bring a 1200-kg car to rest from s rasg2.odzz i6cq0- 2he0pg5a speed of $95\,km/h$ ?    kcal

  An automobile cooling system holds 16 L of water. How much heat does it absyb3ah3e q.2 mxorb if its temperature rises fromabmqe hx .32y3 20$^{\circ}C $ to 90$^{\circ} C$?    $ \times10^{ 6}\,J$

  What is the specific heat of a metal substance if 135 kJ os )modmd,o;o9y:tllx/ yfc7:f heat is needed to raise 5.1 kg dm,:7o ;flo)x s/ym9tlo:d yc of the metal from 18.0$^{\circ}C $ to 31.5$^{\circ} C$ ?    $J/kg\cdot\,C^{\circ} $

  Samples of copper, as.r vxjpgji:b6 x /x+tt/sb4: luminum, and water experience the same temperature rise when they absorb the same amount of :g/i tvxx tbx: 4sb/ +.p6rjsjheat. What is the ratio of their masses? [Hint: See Table 14–1.]$m_{Cu}$ : $m_{Al}$ : $m_{H_2O}$ =    :    :   

  A 35-g glass thermometwi81vnw-q qgew;k 3ms hgfb 3;b31ea (er reads 21.6$^{\circ} C$ before it is placed in 135 mL of water. When the water and thermometer come to equilibrium, the thermometer reads 39.2$^{\circ} C$ . What was the original temperature of the water?$T_{iH_2O}$ =    $^{\circ}C $

  What will be the equilibrium temperature when a 245-g block of copper at 285x(lr l)yyim zu-1j23:zy 2p f6v1sr to$^{\circ}C $ is placed in a 145-g aluminum calorimeter cup containing 825 g of water at 12.0$^{\circ} C$ ? $T_{eq}$ =    $^{\circ} C$

  A hot iron horseshoe (mz2d0zou i92vrvd8w,t)ygb * lass = $0.4\,kg$) just forged (Fig. 14–16), is dropped into 1.35 L of water in a 0.30-kg iron pot initially at 20.0$^{\circ} C$ . If the final equilibrium temperature is 25.0$^{\circ} C$, estimate the initial temperature of the hot horseshoe.    $^{\circ} C$

  A 215-g sample of a substance is heated to 333k- rc1u pyi)s0$^{\circ} C$ and then plunged into a 105-g aluminum calorimeter cup containing 165 g of water and a 17-g glass thermometer at 12.5$^{\circ} C$ . The final temperature is 35.0$^{\circ} C$ . What is the specific heat of the substance? (Assume no water boils away.)    $J/kg \cdot C^{\circ} $

  How long does it take a 750-W coffeepot to bring to a boil,ul v3 yol:j3a.nsv vfnv aj:+s:v *9l 0.75 L of water initially anvv .uf:,o yv*v9vl:nsjj+al33:sal t 8.0$^{\circ}C$? Assume that the part of the pot which is heated with the water is made of 360 g of aluminum, and that no water boils away. $\approx$    min (Round to the nearest integer)

  Estimate the Calorie content of 75 g of candy from the following4vj5 l -wkol.b measurements. A 15-g sample of the candy is allowed to dry before putting it in a bomb calorimeter. The alum l.lk j-5obvw4inum bomb has a mass of 0.725 kg and is placed in 2.00 kg of water contained in an aluminum calorimeter cup of mass 0.624 kg. The initial temperature of the mixture is 15.0$^{\circ}C $ , and its temperature after ignition is 53.5$^{\circ} C$ .    Cal

  When a 290-g piece of irr3j9 i7x;i eyr d;0hdhon at 180$^{\circ} C$ is placed in a 95-g aluminum calorimeter cup containing 250 g of glycerin at 10$^{\circ} C$ , the final temperature is observed to be 38$^{\circ}C $ . Estimate the specific heat of glycerin.    $J/kg \cdot C^{\circ} $

  The 1.20-kg head of a hammer has ay c el6 8li 7lu.nau3n*n7y0pu speed of $6.5\,m/s$ just before it strikes a nail (Fig. 14–17) and is brought to rest. Estimate the temperature rise of a 14-g iron nail generated by 10 such hammer blows done in quick succession. Assume the nail absorbs all the energy.    $C^{\circ} $

  The heat capacity, C, of an object is defined as the amount ofz cb.n, eu) g-re(*3bflxcpv8:kijm; heat needed to raise its temperatu,(lrm 3v-cx):je b. bzfie; g8npcu*kre by 1 $C^{\circ} $ . Thus, to raise the temperature by $\Delta\,T$ requires heat Q given by
$Q\,=\,C\,\Delta T$
(a) Write the heat capacity C in terms of the specific heat, c, of the material.
(b) What is the heat capacity of 1.0 kg of water?    $ \times10^{3 }\,J/C^{\circ}$
(c) Of 25 kg of water?   $ \times10^{ 5}\,J/C^{\circ}$

  How much heat is needed to melt 16.50 kg of silver that is8n 8og:w: 3tchw yme7e initially at 20$^{\circ} C$?    $ \times10^{6 }\,J$

  A 0.095-kg aluminium sphere is dropped from the roof of a 45-m-hi2y;ec ; .gkgnwa)2otigh building. If 65% of the thermal energy produced when it hits the ground is absorbed by the sp2na .k;twgc) yi;go2e here, what is its temperature increase?    $C^{\circ}$

  During exercise, a persopb(f+/ g4 0-ijap8pefe tt cb/n may give off 180 kcal of heat in 30 min by evaporation of water from the skin. How much0gtjp-p/b4+fi/( bp eaef8ct water has been lost?    kg

  If $2.80 \times10^{ 5}J$ of energy is supplied to a flask of liquid oxygen at -183$^{\circ} C$ how much oxygen can evaporate?    kg

  A 30-g ice cube at its melting point is 3n.zksam) o,b;xx5c8; urpbs dropped into an insulated container of liquid nitrogen. How much nitrogen evaporates if it is at its boiling point of 77 K and has a latent heat of vaporization nu8 ;5 sx). bok,xmab3c;sr zpof $200\,kJ/kg$ Assume for simplicity that the specific heat of ice is a constant and is equal to its value near its melting point.    kg

  A cube of ice is taken from the freezer at j5t6q oq ka;a 3g(9tkj7f3rtk -8.5 $^{\circ} C$ and placed in a 95-g aluminum calorimeter filled with 310 g of water at room temperature of 20.0$^{\circ} C$. The final situation is observed to be all water at 17.0$^{\circ} C$. What was the mass of the ice cube?    $ \times10^{-3 }$ kg

  An iron boiler of mass 230 o.krx8mi6lf m9q.b;n kg contains 830 kg of water at 18$^{\circ} C$. A heater supplies energy at the rate of $52,000\,kJ/h$ How long does it take for the water
(a) to reach the boiling point,$\approx$    h (Round to one decimal place)
(b) to all have changed to steam?$\approx$    h (Round to the nearest integer)

  In a hot day’s race, .a9hml+j) bly1 :r xcfa bicyclist consumes 8.0 L of water over the span of four hours. Making the approximation that all of the cyclist’s energy goes into evaporating this water as sweat, how much energy in kcal did the rider use during the ride? (Since the efficiency of the rider is only about 20%, most of the energy consumed d+.x:m9jr al)hyf1bc l oes go to heat, so our approximation is not far off.)    kcal

  What mass of steam at 10wvnk(wj3:n* m fx8g,z 0$^{\circ} C$ must be added to 1.00 kg of ice at 0$^{\circ} C$ to yield liquid water at 20$^{\circ} C$ ?    kg

  The specific heat of mercury le+oh/lv -d9 fj0edk9is $138\,J/kg$$\cdot\,C$ Determine the latent heat of fusion of mercury using the following calorimeter data: 1.00 kg of solid Hg at its melting point of -3.9$^{\circ} C$ is placed in a 0.620-kg aluminum calorimeter with 0.400 kg of water at 12.80$^{\circ} C$ ; the resulting equilibrium temperature is 5.06$^{\circ} C$ .    $ \times10^{ 4}$ J/kg

  A 70-g bullet travelin b h.o*2v6y(m,dsapojoy6 u ze 7ab2m:g at $250\,m/s$ penetrates a block of ice at 0$^{\circ} C$ and comes to rest within the ice. Assuming that the temperature of the bullet doesn’t change appreciably, how much ice is melted as a result of the collision?   g

  A 54.0-kg ice-skater movo(j-jsbr 79v.bw5d nwing at $6.4\,m/s$ glides to a stop. Assuming the ice is at 0$^{\circ} C$ and that 50% of the heat generated by friction is absorbed by the ice, how much ice melts?    g

  At a crime scene, the forensic investigator notes that the 8fjt8u pl:ll9hv3-t;rrr fl ; 1dggg-t8fe4) q.2-g lead bullet that was stopped in a doorframe apparently melted completely on impact. Assuming the bu1grfh8lfve - t jt8;d g 9lp4:;fr -)u3rtqlglllet was fired at room temperature (20$^{\circ} C$ ), what does the investigator calculate as the minimum muzzle velocity of the gun?    m/s

  One end of a 33-cm-long aluminum rod with a diameter of 2.0 cm is kept atncczxk x,4 w+/ 460$^{\circ} C$ , and the other is immersed in water at 22$^{\circ} C$ . Calculate the heat conduction rate along the rod.    W

  Calculate the rate of heat flow by conduction in Example 14–10, assuming that t*xj8q2web 1 jbhere are strong ge2qx b81*bjjwusty winds and the external temperature is -5$^{\circ} C$   $ \times10^{4 }$ W

  (a) How much power is radiated by a tungsten sphere (tc/n5 , e+oew,8dm(q ifq/ uvk45mnm demissivity $e\,=\,0.35$) of radius 22 cm at a temperature of 25$^{\circ} C$ ?    W
(b) If the sphere is enclosed in a room whose walls are kept at -5$^{\circ} C$ what is the net flow rate of energy out of the sphere?    W

  Heat conduction to skin. Suppose 200 W of h94u zur pmaltm1j0(j56l8at f eat flows by conduction from the blood capajjl pltzm 89(tfm610a5uu r4 illaries beneath the skin to the body’s surface area of $1.5\,m^2$ If the temperature difference is 0.50 $C^{\circ} $ , estimate the average distance of capillaries below the skin surface.    $ \times10^{-4 }$ m

  Two rooms, each a curl;mz9 wc;/w is/i8c0.96m ahjgh sl fbe 4.0 m per side, share a 12-cm-thick brick wall. Because of a numblh 9;;s.cl 69c8am0mjzrgfsi hi//w wer of 100-W lightbulbs in one room, the air is at 30$^{\circ} C$, while in the other room it is at 10$^{\circ}C $. How many of the 100-W bulbs are needed to maintain the temperature difference across the wall?    bulbs

  How long does it take the Sun to melt a jykhm+oz; p8lrp* /clcsr3(0 block of ice at 0$^{\circ} C$ with a flat horizontal area $1.0\,m^2$ and thickness 1.0 cm? Assume that the Sun’s rays make an angle of 30$^{\circ} $ with the vertical and that the emissivity of ice is 0.050.    h

  A copper rod and an aluminum rod of the same length and crosstkk -,shgkr. ue 6kc7+j0,r is-sectional area are attached end to enr r. kuk+ 6c,eigs7t,0-kk shjd (Fig. 14–18). The copper end is placed in a furnace maintained at a constant temperature of 250$^{\circ} C$. The aluminum end is placed in an ice bath held at constant temperature of 0.0$^{\circ} C$ . Calculate the temperature at the point where the two rods are joined.    $^{\circ} C$

  (a) Using the solar constant, estimate the rate at which the whole Earth receive6ys,( r;cil k ugb+ot(s energy (g ysi6t ;r,o uclbk(+from the Sun.    $ \times10^{17 }$W
(b) Assume the Earth radiates an equal amount back into space (that is, the Earth is in equilibrium). Then, assuming the Earth is a perfect emitter ($e\,=\,1.0$) estimate its average surface temperature.    $^{\circ} C$

  A 100-W lightbulb generates 95 W of heat, which is di58 ,ipjuhsi 1dssipated through a glass bul 81,ipusijd 5hb that has a radius of 3.0 cm and is 1.0 mm thick. What is the difference in temperature between the inner and outer surfaces of the glass?   $^{\circ}C $

  Suppose the insulating qualities of the wall of a house come zau;u- qlmahq2-di31mainly from a 4.0-in. layer of brick and an R-19 layer of insulation, as shown in Fig. 14–19. What is 2hz1 duq ua ialq-;3m-the total rate of heat loss through such a wall, if its total area is $240ft^2$ and the temperature difference across it is 12 $F^{\circ} $?    Btu/h

A double-glazed window has two panes oz)3dx b qm;f,nf glass separated by an air space, Fig. 14–20. (a) Show that the rate of heat flow through such a window by conduction is given b; f qnm3x,dz)by
$\frac{Q}{t}$ = $\frac{A(T_2-T_1)}{l_2/k_1+l_2/k_2+l_3/k_3}$,
where $k_1$,$k_2$ and $k_3$ are the thermal conductivities for glass, air, and glass, respectively. (b) Generalize this expression for any number of materials placed next to one another.

  Approximately how long should it take 11.0 kg of ice at *ck9cs5nbv- r0; gdgd0$^{\circ}C $ to melt when it is placed in a carefully sealed Styrofoam ice chest of dimensions $25\,cm\times\,35\,cm\times\,55\,cm$ whose walls are 1.5 cm thick? Assume that the conductivity of Styrofoam is double that of air and that the outside temperature is 32$^{\circ} C$.    $ \times10^{4 }$s

  A soft-drink can contains )x1)hf02c )jqzn rjheabout 0.20 kg of liquid at 5$^{\circ}C $. Drinking this liquid can actually consume some of the fat in the body, since energy is needed to warm the water to body temperature (37$^{\circ} C$). How many food Calories should the drink have so that it is in perfect balance with the heat needed to warm the liquid?    C

  If coal gives off $30\,MJ/kg$ when it is burned, how much coal would be needed to heat a house that requires $ 2.0\times10^{5 }\,MJ$ for the whole winter? Assume that 30% of the heat is lost up the chimney.    kg

  To get an idea of how much thermal energy is contained in the w h,yt*v:qv;csj-9 y ihorld’s oceans, estimate the heat liberated when a cube of oci,hv;9 c-syy*v:tjh qean water, 1 km on each side, is cooled by 1 K. (Approximate the ocean water as pure water for this estimate.)    $ \times10^{ 15}\,J$

  A 15-g lead bullet is aat: o0;by -c-nya(phtested by firing it into a fixed block of wood with a mass of 1.05 kg. The block and imbedded bullet together absorb all a0h-c(p a:oy;tyab n-the heat generated. After thermal equilibrium has been reached, the system has a temperature rise measured as 0.020 $C^{\circ} $. Estimate the entering speed of the bullet.    m/s

  (a) Find the total p 8fembs:4j(y6cz*)xj:ccu dgower radiated into space by the Sun, assuming it to be a perfect emitter 8:(* j sj f6udzxcge)c :yc4bmat $T\,=\,5500K$ The Sun’s radius is $7.0 \times10^{ 8}\,m$    $ \times10^{ 26}\,W$
(b) From this, determine the power per unit area arriving at the Earth, $1.5 \times10^{ 11}\,m$ away (Fig. 14–21).    $ \times10^{ 3}\,W/m^2$

  During light activity, a 70-kg person may -fwl *um7q.fngenerate $200kcal/h$ Assuming that 20% of this goes into useful work and the other 80% is converted to heat, calculate the temperature rise of the body after 1.00 h if none of this heat were transferred to the environment.    $C^{\circ} $

  A 340-kg marble boulder rolls off the top of a cmag/i .tqm84 v9 bmlst 6tu,4mn+tm7rliff and falls a vertical height of 140 m before striking the ground. Estimate the temperature rise of the rock if 50% of tgv. ,mm9+48/arb64 mliumttst7qtn m he heat generated remains in the rock.    $C^{\circ} $

  A 2.3-kg lead ball is droppqbd;z7 j;* kjq)bcx5hed into a 2.5-L insulated pail of water initially at 20.0kh *b xd;jz5)q7cq j;b$^{\circ} C$. If the final temperature of the water–lead combination is 28.0$^{\circ} C$, what was the initial temperature of the lead ball?    $^{\circ}C $

  A mountain climber wearsmm moyxg u)px 1q6v1wa;t4 2r; a goose down jacket 3.5 cm thick with total surface areamurwqg;x yp162 m)1ox ;tamv4 $1.2\,m^2$ The temperature at the surface of the clothing is -20$^{\circ}C $ and at the skin is 34$^{\circ} C$. Determine the rate of heat flow by conduction through the jacket
(a) assuming it is dry and the thermal conductivity k is that of down,    W
(b) assuming the jacket is wet, so k is that of water and the jacket has matted to 0.50 cm thickness.    W

  A marathon runner has an average metabolism rate oft b y0ax3nm x.yy)e0(s about $950\,kcal/h$ during a race. If the runner has a mass of 55 kg, estimate how much water she would lose to evaporation from the skin for a race that lasts 2.5 h.    kg

  Estimate the rate at whichc *lj+jxf1 1t,i nwyzl79o d3s heat can be conducted from the interior of the body to the surfacw7 zdllxn,jj 91o *+tfcsiy31e. Assume that the thickness of tissue is 4.0 cm, that the skin is at 34$^{\circ}C $ and the interior at 37$^{\circ}C $, and that the surface area is $1.5\,m^2$ Compare this to the measured value of about 230 W that must be dissipated by a person working lightly. This clearly shows the necessity of convective cooling by the blood.    W

  A house has well-insulated walls 17.5 cm thick (assy 3,c//hnv 3perke-lyume conductivity of air) and 3cy-p /l/,rk3eynev harea $410\,m^2$ a roof of wood 6.5 cm thick and area $280\,m^2$ and uncovered windows 0.65 cm thick and total area $33\,m^2$
(a) Assuming that heat is lost only by conduction, calculate the rate at which heat must be supplied to this house to maintain its inside temperature at 23$^{\circ}C $ if the outside temperature is -10$^{\circ} C$    $ \times10^{5 }$W
(b) If the house is initially at 10$^{\circ} C$, estimate how much heat must be supplied to raise the temperature to 23$^{\circ} C$ within 30 min. Assume that only the air needs to be heated and that its volume is $750\,m^3$    $ \times10^{ 8}$J
(c) If natural gas costs 0.080 dollars per kilogram and its heat of combustion is $ 5.4\times10^{7 }\,J/kg$ how much is the monthly cost to maintain the house as in part (a) for 24 h each day, assuming 90% of the heat produced is used to heat the house? Take the specific heat of air to be $0.24\,kcal/kg$$\cdot\,C$.    dollars

  A 15-g lead bullet travelizrv7159dib)sk1 :nvlfaa r id ay,1t3ng at $220\,m/s$ passes through a thin wall and emerges at a speed of $160\,m/s$ If the bullet absorbs 50% of the heat generated, (a) what will be the temperature rise of the bullet? (b) If the bullet’s initial temperature was 20$^{\circ} C$, will any of the bullet melt, and if so, how much?    $C^{\circ} $

  A leaf of area $40\,cm^2$ and mass $ 4.5\times10^{-4 }\,kg$ directly faces the Sun on a clear day. The leaf has an emissivity of 0.85 and a specific heat of $0.80\,kcal/kg\,\cdot K$.
(a) Estimate the rate of rise of the leaf’s temperature.    $C^{\circ} $
(b) Calculate the temperature the leaf would reach if it lost all its heat by radiation to the surroundings at 20$^{\circ} $C.    $^{\circ}C $
(c) In what other ways can the heat be dissipated by the leaf?

  Using the result of part (a) in Problem 58, takh,m-c a1hh t0ze into account radiation from the leaf to calcum1h-hh zca ,0tlate how much water must be transpired (evaporated) by the leaf per hour to maintain a temperature of 35$^{\circ} C$.    g/h

  An iron meteorite melts when it enters the Earth’s atmospb) zd ;jt9+z dfyu*(pehere. If its initial tez* d9j)d zb;ptu(e+f ymperature was -125$^{\circ} C$ outside of Earth’s atmosphere, calculate the minimum velocity the meteorite must have had before it entered Earth’s atmosphere.    m/s

  The temperature within the Earth’s crust increaq- z2wue e61qbses about 1.0 C$^{\circ} $ for each 30 m of depth. The thermal conductivity of the crust is $0.80\,W/C^{\circ} \cdot\,m$
(a) Determine the heat transferred from the interior to the surface for the entire Earth in 1 day.    $ \times10^{18 }\,J$
(b) Compare this heat to the amount of energy incident on the Earth in 1 day due to radiation from the Sun.$Q_{Sun}$ =    $ \times10^{4 }\,Q_{interior}$

  In a typical game of squash (Fig.:9 w9l xcicp,p 14–22), two people hit a soft rubber ball at a wall unt:pl9, cp w9cxiil they are about to drop due to dehydration and exhaustion. Assume that the ball hits the wall at a velocity of $22\,m/s$ and bounces back with a velocity of $12\,m/s$ and that the kinetic energy lost in the process heats the ball. What will be the temperature increase of the ball after one bounce? (The specific heat of rubber is about $1200\,J/kg\,$$\cdot\,C$)    $C^{\circ} $

What will be the final result when equal masses of icbw3lq 59auuc+n69n zvb7 ab.ne at 0$^{\circ} C$ and steam at 100$^{\circ}C $ are mixed together?

  In a cold environment, a person can lose heat by cok(uq0n8 4t isxq5cf1xnduction and radiation at a rate of x8iuft0n 45xcsk( qq1about 200 W. Estimate how long it would take for the body temperature to drop from 36.6$^{\circ} C$ to 35.6$^{\circ} C$ if metabolism were nearly to stop. Assume a mass of 70 kg. (See Table 14–1.)    s

  After a hot shower and dishwashing, there is “no hot watey x8dth1b0e:9pob z u( wd9(sbk:a0 gp5c.v dqr” left in the 50-gal (185-L) water heater. This suggests t5v 1gy ce:qd .(swx pudoa(z :98h0 kdbpb09bthat the tank has emptied and refilled with water at roughly 10$^{\circ} C$. (a) How much energy does it take to reheat the water to 50$^{\circ} C$? (b) How long would it take if the heater output is 9500 W?    s

  The temperature of the glass surface of a 60-W lirxo 4-zw:3ned ghtbulb is 65$^{\circ} C$ when the room temperature is 18$^{\circ} $C. Estimate the temperature of a 150-W lightbulb with a glass bulb the same size. Consider only radiation, and assume that 90% of the energy is emitted as heat.    $^{\circ} C$