What happens to the wok2w11p2jxmarn0. ,r hndzen, rk done when a jar of orange juice is vigorously shaken?

When a hot object warms a cooler object, does temperature flow betwe(s6nf v quvx-4 *pa6 +t0rvmllr1n1mmen them? Are the temperature changes q t16xmrl+sfm0vv6m - unlv *1nrap(4of the two objects equal?

(a) If two objects of -2ppuq2fel 6d different temperatures are placed in contact, will heat naturally flow from the object with higher internal energy dplu2e fp2-q6 to the object with lower internal energy? (b) Is it possible for heat to flow even if the internal energies of the two objects are the same? Explain.

In warm regions where tropical plants grow but the temperature may /ak6xzrgyqa ;lb ) :4kdrop below freezing a few times in the winter, the destruction of sens bz /yk46:)rqx klaa;gitive plants due to freezing can be reduced by watering them in the evening. Explain.

The specific heat of water is quite large. Expllzgfc/hcj *8, 9.sxtqain why this fact makes water particularly good for hea.qh l 89 tzjx,cfsg/*cting systems (that is, hot-water radiators).

Why does water in a metal canteen stay coglwn hfaj 3p ::1b-zb1oler if the cloth jacket surrounding the canteen isnha1 -w :glbf3zj1 :pb kept moist?

Explain why burns caused by steam on the skin are often more severe than :;6l2q 7d6nltfl vz ghburns caud 67; 6f g:nvlthqzl2lsed by water at 100 $^{\circ} C$ .

Explain why water cools (its temperature drops) whe mt+s t/ ipm0xm ,hnpb;p4c9o:n it evaporates, using the concepts of latent heat and icsbi ;pmp9t, ton:p m+ h/4x0mnternal energy.

Will potatoes cook faster if the water is boiling fa3;acn3ufg w9n cou3p+ ster?

Does an ordinary electric fan cool the air? Why or why not? If noy7uh* d8- ouec.*,erin1qp9qcc vkn9h)ia p6t, why use it?

Very high in the Earth’syp( j9;h)r;jwzzr r2 c atmosphere, the temperature can be 700 $^{\circ} C$ . Yet an animal there would freeze to death rather than roast. Explain.

Explorers on failed Arctic expeditions have survive-1:c 8(jqfim6mvk lanp pb -g9d by covering themselves with snow. W fgvja1i mqpclm-:69b-n(p 8 khy would they do that?

Why is wet sand at the beach cooler tqnamqcr i58(cviorqwe1;p 48miu3+y rim*95 o walk on than dry sand?

If you hear that an object has “high heat content,” does that mh44)psg fi.vjean that its temperaturpsi 4vfjgh) 4.e is high? Explain.

When hot-air furnaces are used to he2z egr4k/aesn 4 k6*bxkls(3vat a house, why is it important that there be a vent for air to return to the furnace? Whl 2ev r kb s*axs4g63nz(kk/4eat happens if this vent is blocked by a bookcase?

Ceiling fans are sometim6d0cmau)(pdh es reversible, so that they drive the air down in one season and puuhm)(dp6cd a 0ll it up in another season. Which way should you set the fan for summer? For winter?

Down sleeping bags and parkas are often specified as so manym hc9z+orx* r gg7(((rid m)1y+wih fv inches or centimeters of loft, the actual thickness of the garment when it is fluffed up. Explaixm*(hircg+fz g 9+m)(roh wr7vyi( d1n.

Microprocessor chips have a “heat sink” glued on top that looks likexo-tm:-q mow ( a series of fins. Why is it shapedmw( to- qmx-:o like that?

Sea breezes are often encountered on sunny days at the shore of a lar+(3 ru zz uq:o/b7ta3 ciq9lysnt4tt9ge body of water. Explain in light of the fact that the temperature ua:zqcutntzrl9 /93y+4t io7 qt(3bs of the land rises more rapidly than that of the nearby water.

The floor of a house on a foundation np7pelmyq* ul-el/k4ib:5 b6 under which the air can flow is often cooler than a floor that rests directly on the ground (such as a :l/ ebk ipub5y67-l n4emqpl *concrete slab foundation). Explain.

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

Explain why air temperature readings are always taken with the thermometer inpz w*j6r,0div(zzdb- the shade0r z,bzd*jdpz-vi6( w.

A premature baby in an incubator can / avdqi9cz1 9fbe dangerously cooled even when the air temperatuqvdf/c9 i19 azre in the incubator is warm. Explain.

Why is the liner of a e+37se ; genrhnha )s4thermos bottle silvered (Fig. 14–15), and why does it have a vacuum betweensnhe7 +e3);eh sna4rg its two walls?

Imagine you have a wall t rkv5kkctg5nph *xy a: 6yi)07 5pcx*what is very well insulated — it has a very high thermal resistw*)ha xy5 gt56r5p*0v c:kx pnkiyk7cance, $R_1$ 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)lxd)qj,,cw9 9g*p qb x ventilation around edges; (2) through the frame, particularly if it is metal; (3) through the glass panes; and (4) radiation. (a) For the first three, what is (are) tjgb ,* 9qw9x )pqldx,che mechanism(s): conduction, convection, or radiation? (b) Heavy curtains reduce which of these heat losses? Explain in detail.

A piece of wood lying in the Sun absorbs more heat than a piece of shiny metalxmcmx4 l89 r)x 8gc 9 s:-iqmdr1 9g,obocol:k. Yet the wood feels less hot than the metal when you pick it up. Expmcs4l1q8l 9 9 :g doxcxog9m-) :orrxmbc,i 8klain.

The Earth cools off at night much more quickly when ujp9.1 is;q0fp h j o+ppr/g4nthe weather is clear than when cloudyu.0sq ;pp/hg fjj 1npir 9p4+o. Why?

An “emergency blanket” is a thin shiny (metal coated) plastic foil. E:)3atm/a 0(xaoe pb/- qaelwp xplain how it can help to keep an immobile peraq-o l)//ppa:eb e3m0xw t(aason warm.

Explain why cities situatb;5 n.8f1 z:gl4caf1e ncp sv/gxilt:ed by the ocean tend to have less extreme temperatures than inland citi/vx l8l5gn1speci4f.b1;c tnafgz ::es at the same latitude.

  How much heat (in joules) is required to raise the temper;ypm /shaxi) +*l bsg1r2g7ypv g4aa5ature of 30.0 kg of water f+a vr5yg;ig x a1*ps sapmhy)b7g/4l2rom 15 $^{\circ} C$ to 95 $^{\circ} C$ ?    $ \times10^{7 }\,J$

  To what temperature will 7700 J of heat raise 3.0 kg of water that is initiallywf7zir)qse 5oy( : t6z a)r7eqw:5sy z(f oi 6ztt 10.0 $^{\circ} C$ ?    $^{\circ} C$

  An average active person cons m216i ezkcj1uumes 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 a unitskvfk2e16adu.xqbi2 + gl1o0 of heat in the British system of units. One Btu is defined as the heat needk 1usvx ka0q6gel.df21bi o+2ed to raise 1 lb of water by 1 F $^{\circ} $ . Show that
1Btu = 0.252kcal=1055J

  A water heater can generat lpv yi4bm 73r)3szl9g47xbsne $32,000\,kJ/h$ How much water can it heat from 15 $^{\circ} C$ to 50 $^{\circ} C$ per hour?    kg/h

  A small immersion heater is rated at 350 W. Estimatetqrolhj 6 5.i8 how long it will take to heat a cup of soup (assume this is 250 mL of water) fr h.5r lotjq86iom 20$^{\circ} C$ to 60$^{\circ} C$ .    min

  How many kilocalories are generated when the braq lr7na6 h59rrdjcm05 kes are used to bring a 1200-kg cal79cnr6h550a qjm rd rr to rest from a speed of $95\,km/h$ ?    kcal

  An automobile cooling system holds 16 L of water. How much heat does it abk im8k hro41 9djk+og2sorb if its tempeh 1kgdoom8+r i92kj k4rature rises from 20$^{\circ}C $ to 90$^{\circ} C$?    $ \times10^{ 6}\,J$

  What is the specificjchis+)sti/qz 2 m6877c zj np heat of a metal substance if 135 kJ of heat is needed to raise 5.1 kg of the metal82j 7ss7qnj+i6h zzpitm)c/ c from 18.0$^{\circ}C $ to 31.5$^{\circ} C$ ?    $J/kg\cdot\,C^{\circ} $

  Samples of copper, aluminum, and water experience the same temperatureqah frw5 t0:75ufwpg3 rise when they absorb the same amount of heat.55: fwgtua0wqp7hf 3 r What is the ratio of their masses? [Hint: See Table 14–1.]$m_{Cu}$ : $m_{Al}$ : $m_{H_2O}$ =    :    :   

  A 35-g glass thermometer rb0up4m+ bk,egm :q 3xveads 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 285c*h rc)*l+l mw$^{\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 1zcg/kkgoa .+qvx/ /t9ix ke8 (mass = $0.4\,kg$) 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 heated8w-kob-udxg0 to 330$^{\circ} C$ 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 coffeepo yzema. -h7zr2itu m28t to bring to a boil 0.75 L of water initialz ui r 2ehza2-ymt.m87ly at 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 following measurements. ofm)f 1 bif0acxbq k-y5 g/2g5A 15-g sample of the candy is allowed to dry before putting it in a bomb calorimeter. The aluminum bomb has a mass of 0.725 kg and is px /g f-gqfm 1)ac0bibyo25kf5laced 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 ozy8 2u fnqh)e5f iron 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 a sptsox+ o6vd ,,jeed 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 obje- 7zdd77dp ; fxfssht 0a,e yj)et9m4kct is defined as the amount of heat needed to raise its tempesks0txtha,z;jfee fy 7)74-d79d dpm rature 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 neededn g-y*5g,ph+djgy(r5nd ;kin to melt 16.50 kg of silver that is initially at 20$^{\circ} C$?    $ \times10^{6 }\,J$

  A 0.095-kg aluminium sphere is dropped from the roof of a 45-m-high buil9)vgk ;4 ul23t )urhuc tozy(+no0:d f oep:wsding. If 65% of the thermal energy produced when it hits the ground is absorbuyr(9k2+nw))h o3l pevdfztg; ouo:0tu :4c sed by the sphere, what is its temperature increase?    $C^{\circ}$

  During exercise, a person may give off 180 kcal of heat in 30 min by evaporationw+*l95dmy40(kk xudaag y ll7 of water7yuylm 4dld0(lwakkg95 x a* + from the skin. How much 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 dropped into an insulated container of- m)3(8 kfz k,rz- )hzhknvfny liquid nitrogen. How much nitrogen evaporates if it is at its boiling point of 77 K and has a latent heat of vapork n, vhzhm)fyfk38 -n (zzrk-)ization of $200\,kJ/kg$ 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 fs-qpm6i+qy su*j 4zw99xs1 g-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 kg contains 830 kg of j-f89g x 2 lyh5x--xok-hoqf qi6veq/ 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, a bicyclizqc uf z-mqk/hdg,137 st 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, hom/ 1,cf hg3 ukd-qz7qzw 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 does go to heat, so our approximation is not far off.)    kcal

  What mass of steam at 1;2s3-9t vu erx px32ow swco6o00$^{\circ} C$ 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 isfc 0(e7fm/o8jy -a dry $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 travelinb3 d d xpg83qyqm.oo6uf nj*2.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 movi/h /f ;y fgzi jlemh7wsgt(d gm8319g;ng 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 invs ws (o,nep m7(t8uq5 *bg 3+fv6tymjhestigator notes that the 8.2-g lead bullet that was stopped in a doorframe apparently melted completely on impact. Assumin g78whqt 5p +,mb3eujsns*6f(ytovm ( g the bullet 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 2npq rim26iyq1d5+ uz5ldc q6 a diameter of 2.0 cm is kept at 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 thw4.rwsg*u82ypd 4vl 6- m vo gfrm l5;xosm:d2ere are strong gusty winds andgmgpry sm s4dx2owu4-w62r 5* ml l8:dv.v;fo the external temperature is -5$^{\circ} C$   $ \times10^{4 }$ W

  (a) How much power is radiated by a tungja-fsy,:,r k( e/lg ykono;4isten sphere (emissivity $e\,=\,0.35$) 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 heat flows by conducce0dd.1 e.kxa tion from the blood capillaries ec0dexd k1. .abeneath 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 cube 4.0 m per side, share a 12-cm-thick brick wall. Beezxd jp9i)j;gelo;fwg3rf:; a6-s+i cause of a number of 100-W lightbulbs in one room, the air ixl ;3esp6a fwgio zjr;di)jg;9 +f:e-s 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 Suntaj96b f1g c;p to melt a 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 cross-sectional k2 j6vlrce si9w:8 8vearea are attached end to end (Fig. 14–18). The copper end is placed in a furnace maintained at a constant temperail89jwv s 6erec28k:v ture 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 constan 04ypuwryrvb z84 +k ub+i2r,rt, estimate the rate at which the whole Earth receives energy from thu ryvw8ry0 ,bz+4+ rr4i ub2pke 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 dissipated through a ivq0sz1 a25mt glass bulb that has a radius of 3.0 cm and is 1.0 mm thick. What is the difference in temperature between the inner and z10im 5 q2tvasouter surfaces of the glass?   $^{\circ}C $

  Suppose the insulating qualities of tptu62hfpgmr3.7yx wtm z;:*she wall of a house come mainly from a 4.0-in. layer of brick and an R-19 la;g23mp*hs:fyz u6rmt .txpw7 yer of insulation, as shown in Fig. 14–19. What is 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 of glass separated by an air space, Fig. 14af*ana qs6lni)9 7a .u–20. (a) Show that the rate of heat flow through *a)fs.a9iqaa7nun6l such a window by conduction is given 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 kont 5/s c+wd1eg of ice at 0$^{\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 about 0.20 kg of liquxe3in742 rqu sid 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 world’(fbanz oep ;15s oceans, estimate the heat liberated when a cube of ocean water, 1 km on each side, is cooled by 1 K. (Approximate the ocean water as pure water for this estim(zo ;1fenpa5 bate.)    $ \times10^{ 15}\,J$

  A 15-g lead bullet is tested by fq.y tw2, q*wr kuw 008s7mqnebiring it into a fixed block of wood with a mass of 1.05 kg. The block and imbedded bullet together absorb all the heat generated. After thermal equilibrium has been reached, the system has a temperature rise measured as 0.02q08wt qr,unmw s0. ekqw*7y2b0 $C^{\circ} $. Estimate the entering speed of the bullet.    m/s

  (a) Find the total power radiated in24qj m :fxq6q7 qvzqz vk/70qo zjz59fto space by the Sun, assuming it to be a perfectfzvjq7qvq2f q jxoq9mzz0 q: 5k67z/4 emitter at $T\,=\,5500K$ 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 pern;gil-pdps 5cj f r x 7urbk:3qg9.)f-pz0 3uvson may generate $200kcal/h$ 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 o0m khr2h/2 qzqff the top of a cliff and falls a vertical height of 140 m before striking h/22kzh0q rqmthe ground. Estimate the temperature rise of the rock if 50% of the heat generated remains in the rock.    $C^{\circ} $

  A 2.3-kg lead ball is d,yn r7x fho)i2n 05pnuropped into a 2.5-L insulated pail of water initially at 20yno n x5purfn7),2hi 0.0$^{\circ} C$. 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 wears a goose down jacket 3.5 cm thick with total surface ar:z+l9q(( s rsqer/q. ktfwr9eee rr9qq(/tfse(wkz: s +lr .9qa $1.2\,m^2$ 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 averay -d h+ie5*n7fcv3hxkge metabolism rate of 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 which heat can be conducted from the ituul eo.s ;q+hjt8i07nterior of the body to the surface. Assume that the thickness of tio0 qe jtl+.uh 8ts;i7ussue 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 t744w l1e bkb -z5qa4suuup5qg hick (assume conductivity of air) and area gw1pq au s4z ue5l7bubq5k -44$410\,m^2$ 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 t+bmn3;q3hnl ;w(qh qv raveling 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 Prz.a+cd s3s- yfoblem 58, take into account radiation from the leaf to calculate how much water must be transpired (evaporated) by the leaf per hour to maintain a temperature ofs.3dyfsac-z+ 35$^{\circ} C$.    g/h

  An iron meteorite melts when it enters the Earth’s atmosphere.idrj tsm,9-f s8ml(fg,4 c5as If its initial temperature wl9,d,-ts 4m sj5c im(sf8rfagas -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 increaslz 9+(+qvnyx fxz/pu *es 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. 14–22), t4*z2 wtp g(dtuj.dd+owo people hit a soft rubber ball at a wall until they are about to drop due to dehydration and exhaustion. Assume that t2p+.utodz*(gd4 dw tj he 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 ic)-dw 9lo-mx- z1 exwide at 0$^{\circ} C$ and steam at 100$^{\circ}C $ are mixed together?

  In a cold environment, a person can lose heat byd:(sx(7ortgguk2qk md7- h(zs 2hy-j conduction and radiation at a ra-o2dskm :dh t(jxug 72(-qrhs(kzy 7gte of about 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 water” left in takl7*w4 c:ohklyd als0m9, 3y he 50-gal (185-Lmlo:0 lka3s,d cwa7l9h4k *yy) water heater. This suggests that 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 surfx0vg ,zlx 5cnc yvy7 w7nd/;*pace of a 60-W lightbulb 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.    $^{\circ} C$