What happens to the work done when a jar of orange j itlelu0e 8f64uice is vigorously shaken?

When a hot object warms a cooler object, does temperature flow between them? Ar3e/i8 xhguh (gm km2(pe the temperature changes of the two objects xhm gkmg8uep( /2 3ih(equal?

(a) If two objects of different temperatures are pbp ) +emzy:fj*laced 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+ ybzj:fp *e)m heat to flow even if the internal energies of the two objects are the same? Explain.

In warm regions where v6ytrq mhffp u7-v9 )/3kg5nztropical plants grow but the temperature may drop below freezing a few times in the winter, the destruction of sensitive plants due to frk9u6p)3 7fnqgrv5tvzh -m y f/eezing can be reduced by watering them in the evening. Explain.

The specific heat of water is quite large. Expl wa4o)kz9va,b+rk ex1uuk 5s 5ain why this fact makes water particularly good for 9z 4os,u5xub5) avrakk+e kw1heating systems (that is, hot-water radiators).

Why does water in a metal canteen stay cooler if the cl 2hk9o2l 6t -:gjifyrwoth jacket surrounding the cantetko rlf2- gi2jh:9w6yen is kept moist?

Explain why burns caused by steam on the skin are often more sever0ae79 3d8p ti*icwx sje than burns caused by water at 100 ix 0i t awjcp93*de8s7$^{\circ} C$ .

Explain why water cools (itsw e w,fow.w:d:-y4iod-m. wygozj*2o temperature drops) when it evaporates, using the concepts of latz.moy:.fo4do--2o y ww,ew *wig:wjdent heat and internal energy.

Will potatoes cook faster if the water is boiliu6wkzsqcb 50 0ng faster?

Does an ordinary electric fan cool the air? Why ov 2v5jv( v:egb.d lqc:s42vgw r why not? If not, why use it?

Very high in the Earth’s atmosphere, the temperature can be 700 e(o (pchwvi*8rlx x6qyohy2 zg6v1**$^{\circ} C$ . Yet an animal there would freeze to death rather than roast. Explain.

Explorers on failed Arctic shn0epfb/ ,gwq,.l,g )x u*z(ra5vbd expeditions have survived by covering themselves with snow qg dne*rb(bp.)x f shg,w/,,a0uz5v l. Why would they do that?

Why is wet sand at the beach coo, y22 owwq0pv)xmqr 9gler to walk on than dry sand?

If you hear that an object hasl gpque4l+ir 9;;o1 hb “high heat content,” does that mean that its temperature is high? eg1; ilb+q4 ;hpol9 ruExplain.

When hot-air furnaces are used to heak 9hbm)y30x, rv j5rbgt a house, why is it important that there be a vent for air to return to the furnace? What happens 5 ) h0rgkjxy,rvmbb39if this vent is blocked by a bookcase?

Ceiling fans are sometimes reversible, so that they drive the air down j3z6pa55v tiyye )xtsi+ e t8 qqk)(:win one season and p(6 i)eqq 5kw+tvta s3:yxztj5)ep 8yiull 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 many inchessm81smltrkg / w(t8 d3 or centimeters of loft, the actual thickneskm3 r 1(t w8dtsms8lg/s of the garment when it is fluffed up. Explain.

Microprocessor chips have a “heat sink” glued on top that looks like a +.e+)-ho xhroe( kco8k q +hwfseries of fins. Why is it shaped like tha8.orxwe hchf+q(o)koe ++-h kt?

Sea breezes are often encountered on sunny dayudy- 3q+wbk/e k e),vgs at the shore of a large body of water. Explain in light of the fact that the temperature of the land rises more rapidly than tw/vqg u,ked-)by +3kehat of the nearby water.

The floor of a house on a foundation under which the air can flow is oftev x/qzq5 0b4pnn cooler than a floor that rests directly on the ground (suc 4qbp5/q0xznvh as a 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 temperatu f+d6 tq.q.7n 5dlkajhre readings are always taken with the thermometer in the sh adtn6j.kd 57.qqf h+lade.

A premature baby in an incubator can be dangerously cooled even wheq: n9kumm nqhm:y48 ;nn the air temperau:mmyhqnnmk98 : n;4q ture in the incubator is warm. Explain.

Why is the liner of a thermos bottle silvered (Fig. 14–15), and2hyf 53h8n/4qfw kgfq why does it have a va5/38qfw h ynh2gfqk 4fcuum between its two walls?

Imagine you have a wall that is very well insulated — it has a very higbq/liyxpw * /b6 fkh)tnh( l 25wf50aqh thermal resistan)*(bpt5ffxq2qhn al/6w hw/50 byi lk ce, $R_1$ 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 b ubhx4n i9y*7) h uakym(l+l*sy the following processes: (1) ventilation around edges; (2) through the frame, particularly if it is metal; (3) throuli yb xmah*s u 4yuk*97l)(nh+gh 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 in the Sun absorbs more 0fnoq8a3+cd1qy18b;lif,zpsyf zf 8 heat than a piece of shiny metal. Yet the wood feels less hot than the metal when you pick it up. f+c1oylps qffay 3b8n8f;i08zz ,1qd Explain.

The Earth cools off at night much more qjq lmz ua7y+/e9 ) hkaj8e0hz 8yh-f7tuickly when the weather is clear than whez-et7 0 a7hu eyj8mljqz)y k8h 9hf/a+n cloudy. Why?

An “emergency blanket” if+6 f at czeo(e66t vbd9mo ,rqc;zo8(s a thin shiny (metal coated) plastic foil. Explain how it can help to keep an immobilrft(6tb,moe(cz + 8 fovcd6z 6 oeqa;9e person warm.

Explain why cities situated by the ocean tend to have less ,+d(hwjy1kn yr z-cumt,yt. ; extreme temperatures than inlc+h(y ,wndjyu- 1 ,km ztrt;.yand cities at the same latitude.

  How much heat (in jouleso xd8wlq9r*by)2i47du u cru5) is required to raise the temperature of 30.0 kg of water from 159cuy4 irbrlqdw 7u5d2*xou8 ) $^{\circ} C$ to 95 $^{\circ} C$ ?    $ \times10^{7 }\,J$

  To what temperature will 7700 J of pfq*1b 30ijqqef klu )+f4pk3heat raise 3.0 kg of water that is initially at 10fk plqfkp)q e 3b3ijfqu1+*40.0 $^{\circ} C$ ?    $^{\circ} C$

  An average active person r6j gu/x u;3k6amqku* consumes 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 unit of heax i8:dhqb / :ywh,u+rdt in the British system of units. One Btu is defi: w,q y8rihuhbdx+d/:ned as the heat needed to raise 1 lb of water by 1 F $^{\circ} $ . Show that
1Btu = 0.252kcal=1055J

  A water heater can generatarv/5,ckw ms re6ia1d4+7x w5ee vh;ke $32,000\,kJ/h$ 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. Estimate how ln*fxr g6r/pz27,9/ uzjyv/zmezk 6azong it will take to heat a cup of soup (as vu2r/ z6/z gmzkpzn/e9 ,a*fj zy7r6xsume this is 250 mL of water) from 20$^{\circ} C$ to 60$^{\circ} C$ .    min

  How many kilocalories are generated when the brakes are used to bring a 12c)1ayps toh y) t+m7wr4wn +:8wuwhm ;00-kg car to rest from a speed)y ps8r h)o: ;ht7mw4 atcwwnu1y+ +mw of $95\,km/h$ ?    kcal

  An automobile cooling system * m6p+nyyy e*nholds 16 L of water. How much heat does it absorb if its teyn*6* peym+ ynmperature rises from 20$^{\circ}C $ to 90$^{\circ} C$?    $ \times10^{ 6}\,J$

  What is the specific heat of a metal substance if 135 kJ of heat is needed to r4 ww-t6qx/ ixb o1axi/aise 5.w x -/ t/xb4q1xi6woia1 kg of the metal from 18.0$^{\circ}C $ to 31.5$^{\circ} C$ ?    $J/kg\cdot\,C^{\circ} $

  Samples of copper, aluminum;(hjsqk5i**mkzd:yj6e2b av , and water experience the same temperature rise when they absorb the same amount of heat. What is a26(;ekz*kj m djvy*q h:is b5the ratio of their masses? [Hint: See Table 14–1.]$m_{Cu}$ : $m_{Al}$ : $m_{H_2O}$ =    :    :   

  A 35-g glass thermometer reads 21.6relw d o3v9(7y$^{\circ} C$ 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 28gn((*zv 8r o)ozma a2clu,* az5$^{\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 (mass 4 zbkq 9:/gozf= $0.4\,kg$) 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 3-o335 )kg cs+ gyn,it0 mwwal3hf7yzd30$^{\circ} C$ 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 bri . 59wh,7rdx.o+ 0k/gzcmourhl k/krlng to a boil 0.75 L of water initially a+9ok grl.lkromucwr0. 5 z h7xh /d,/kt 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 onp- q)6tuike q* j*6ifrom the following measurements. A 15-g sample of the candy is allowed to dry before putting it in a bomb calorimeter. Tj 6* ut-en*iipko )qq6he aluminum 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 iron7pl.sc7o 0b/9plu mcr 4( zjux 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 speen3sws7p7, + m rdkqx2jd 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 definivq7v dkj6 3c6ed as the amount of heat needed to raise its tem vc366d7ij kvqperature 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 thatf zmn9wl z;rw0e z98y3 is initially at 20$^{\circ} C$?    $ \times10^{6 }\,J$

  A 0.095-kg aluminium sphere is dropped from the iugz.7 l4c;ug giptk 0w)fr18zh5 )hiroof of a 45-m-high building. If 65% of the thermal en.f4 i5z khzr7u )lhu g81p;)tig wgic0ergy produced when it hits the ground is absorbed 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 evapora vb-47h wxyiney)(r 3ck3ej )ution of water from the skin. How 7eu34)kbx-yiv jewcr( )hy 3nmuch 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 me /)j8rf*e orkd ltjr90m)k9lilting point is dropped into an insulated container of liquid nitrogm rl9let) j8/d f)0jk*r9rkoien. How much nitrogen evaporates if it is at its boiling point of 77 K and has a latent heat of vaporization 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 -xqf1gl,e+ ho/iwq69 a8.5 $^{\circ} C$ 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 83u 9fk7.eelj0zbwj o+30 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, a bicyclist consumes 8.0 L of water ofy8-wx:e 74 8zjv jlhvver 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 ride8x7 hjvze-:yw4flj8 vr 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 100b-ysws) 3;4h jv vxre9$^{\circ} C$ 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 merrsw sovh791q.- m 2vn6+dz ggkcury is $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 travelinsfs :n g5a-lne03d7i9t8 fxjng 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-skaterkru mx 0yda +;qm/t98pyc)9o i moving 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 8.2-g lead bullpdg.qhjkt3 aa 0 ( 5c)eq4da6get that wq.d(cj et4dp0g ak)hg35a 6qaas stopped in a doorframe apparently melted completely on impact. Assuming 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 a sskxms/:o5 /i:3gckbdiameter 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 t3kclzg/1scph l * dy mdbv2q5vl, .6;uhere are strong gusty winds and the external temperac3ymv dlq16.sk;v zg,b/ c p5*dll2uhture is -5$^{\circ} C$   $ \times10^{4 }$ W

  (a) How much power is radiat:l) 5lxfjj85v8 nh zx+ui3 bised by a tungsten 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 sk l24stgia*arz:z w+ 4tin. Suppose 200 W of heat flows by conduction from the blood capillaries beneath the skin to the body’s surface arrz*a tl+44s 2 wz:igtaea 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, vdvl 2*v7 6 0avuup3zyshare a 12-cm-thick brick wall. Because of a number of u plud*vvz6 07y32vva100-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 v/(( ncm9wntpjrj/ g 6the Sun 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 areas u(f/wsd7/hw 1lgrj, are attached end to end (Fig. 14–18). The copper end is placefuw w//(1 sdl7,hgrjs d 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 wholehcj d1qr/i:an 5+fnu) Earth receives energyuq+5hn:djfa ic1 n/r) 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 dissipated thrl)1nukv :h;:yfsj4kl ough a glass bulb that halkklj1v4s f::u; nh)ys 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 wallk8at-xuc rlkc:3-)o6ie so + j of a house come mainly from a 4.0-in. layer of brick ando+jek ox3-i6 cuc) ast:rk-8l an R-19 layer 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 th8hn;r8a 6yygqs, )sn wo panes of glass separated by an air space, Fig. 14–20. (a) Show that the rate of heat flow through such a window by conduction is gg hy88nhs;a)n y ,sq6riven 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 ta,ru :b-xkj-qpke 11.0 kg 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 agfpj t+::e9 yr22gmokbout 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 l o/ ,5k .p6pmxwp6tuythe world’s 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 espp wo.6txk6 ulmp,/ 5ytimate.)    $ \times10^{ 15}\,J$

  A 15-g lead bullet is tested by firing it into a fixed block of wood withk.p1*o:9a i 9ggjlfx p a mass of 1.05 kg. Thlj9k:xpi9 ap ofg1*.ge block and imbedded bullet together absorb all the heat generated. After thermal equilibrium has been reached, the system has a temperature rise measured as 0.020 $C^{\circ} $. Estimate the entering speed of the bullet.    m/s

  (a) Find the total power radiated into space by the d g o1guotivh, 85avsb+,k+6bSun, assuming it to be a perf1b 8odvg5ta oh+ g6v,ik+su,bect 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 person may generatelnfv5vr ts(92 $200kcal/h$ 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 rnr.d+/ w n ;u:7wyz7drd i*(zukg5m bvolls off the top of a cliff and falls a vertical height of 140 m before striking the ground. Estimate the temperature rise of the rock if 50% of the heat generate5dk7d/znub;wyd(v.+ w ru rn7gz m:*id remains in the rock.    $C^{\circ} $

  A 2.3-kg lead ball is dropped c8 vdwfk53+rqinto a 2.5-L insulated pail of water initially at 20.0cr+d85fkv q 3w$^{\circ} C$. 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*etwv)0+.g(es0,vf rpp.ql xbdi h .c goose down jacket 3.5 cm thick with total surface area lsce wx(*r.tg0p) e qhfb+.0vdv pi .,$1.2\,m^2$ 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 ratej mx;c/fkrkyyk 3/99l*bgi - i 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 conducfk;hy(jkoak lw6 t. 08ted from the interior of the body to the surface. Assume that the thiokw.kljy6 hk; 0(t8f ackness 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.cjw 1)bf/x8vr4 /xuaw 5 cm thick (assume conductivity of air) and areaj4b xcav //)f uxw8wr1 $410\,m^2$ 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 traveling at70 mpn /nyspct6c* 3zq8oc/vv $220\,m/s$ 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, take into v/npb *+l p6 nk.9cqiepsuz--account radiation from the leaf to calculate how much water must be transpired (evaporated) by the leaf per hour to mai*s l-z -qnp9vpp6b k.u/cein+ntain a temperature of 35$^{\circ} C$.    g/h

  An iron meteorite melts when it enters the Earth’s atmosphere. Iy; 9b;j:nidej v.8qdgtn..a hf its initial temp: v. jgn; j8ddi;h ..tanyq9beerature 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 )ahwjje* 4ov 3c,k+glthe Earth’s crust increases 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), j-yh wq5o1v5euyu9g5two people hit a soft rubber ball at a wall until they are about to drop due to dehydration and exhaustion. Assume that the ball hits the wall at a velo uvu-gwq9hy 51oy e55jcity 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 ice at 0r ,hh4rw)iweq:5adjhb) s 95d6p + nbv$^{\circ} C$ and steam at 100$^{\circ}C $ are mixed together?

  In a cold environment, a person ca f3(8oo:8jhd ed3xfadn lose heat by conduction and radiation at a rate of about 200 W. Estimate how long it would take for the body temperature to drop fr3dfojfde8ad ( ox8 h3:om 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 dishwashio0qf)di : lx1p1h(iusng, there is “no hot water” left in the 50-gal (185-L) water heater. Thisix(o0: upfds) 1q1i hl 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 surface ot8-h44k 04g9yz5e io rqesasof 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.    $^{\circ} C$