What happens to the work done when a jg:y)ydk mmv;mo +e(i2ar of orange juice is vigorously shaken?

When a hot object warms a coh(,h)oc3 )1oogqxk vqsf3z 6toler object, does temperature flow between them? Are the temperature cg ztv3o,kh))c 1(qfoxoq63 shhanges of the two objects equal?

(a) If two objects of different temperatures are placed in ,;z 4m occr6 o0w(gza* th9egtcontact, will heat naturally flow from the object with higher (z ogr*; 9oahcw4mtzetgc60, internal energy 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 drop belov0kaqy(i6 sub d0ze f,2g /7ekw freezing a few times in the winter, the destruction of sensitive plants due to freezing can be reduced by watering them in the evening. Expla7d0 f 0eibvk2qgkya,sue(z/ 6in.

The specific heat of water is quite large. Explain wh+so6o*x zh 7yo-ou1hi y this fact makes water particularly good for heating syshhy *6 1oi7osox+zu-o tems (that is, hot-water radiators).

Why does water in a metal canteen stay cooler if the cloth j oab)m t7hsd)t6sk qb 30*bt(backet surrounding the canteekqmh6tt)bt(d *b 3s 7bao)0sbn is kept moist?

Explain why burns caused by steam on the skin are oftee3 kmqa2c80 e,5txb obn more severe than burns caq3a,m eco b5b8e2kx0 tused by water at 100 $^{\circ} C$ .

Explain why water cools (its temperature drops) when it evaporates, using the co:i6(i et8cg l-z7vqs16j 2)xqae-dleaj hk:cncepts of latent heat ai8:l1 -e d ec 6 (2zqqhlj):jt67xk as-vieacgnd internal energy.

Will potatoes cook fast:)l )aimyn0l yer if the water is boiling faster?

Does an ordinary electric fan cool the air? Why or why not? If nog7ork o6fl 6,rf 7;w5qn i*foot, why use it?

Very high in the Earth’s atmosphere, the temperb bcd9kw;u4o1 ature can be 700 $^{\circ} C$ . Yet an animal there would freeze to death rather than roast. Explain.

Explorers on failed Arctic expeditions have3syp* hb8,qs 1j5amgqdq2na mmzjo//e. j k*+ survived by covering themselves with snboekm .*pj j s3+yq na* zd185mh/,/2qsgjmaq ow. Why would they do that?

Why is wet sand at the beach cooler to walk on than dry q;rhj xl/ob-5, vu- v.or rroec/f- 2ksand?

If you hear that an object has “0f tdeq i;a/rq42aqq7high heat content,” does that mean that its temperature is high? Explaia a d0r tqqf;74eqq/i2n.

When hot-air furnaces are used to heat a house, why is i94;oy mbp3hx,ryk)8-7bke ira9liw i t important that there be a vent for air to return to the furnace? What hax byh89rilbkkwpo;y -4eii39, )m ra7ppens if this vent is blocked by a bookcase?

Ceiling fans are sometimes reversible, so that they drive the air down in onedsxt +xqcsc2b5*s u39 season and pull it up in another sea9c*3qbscx s d5 u+txs2son. Which way should you set the fan for summer? For winter?

Down sleeping bags and parkas are often specified as so man7rdm6 m uo)z 4pzcef21y inches or centimeters of loft, the actual thickness of the garment when it is fluffed up m)f74rmec1z 2od6z pu. Explain.

Microprocessor chips have a “heatz4 f/fr t*m),ll, qmn9qepz)a sink” glued on top that looks like a series of fins. Why is it shaped like 9mqlnm,la ,fzez )*prqf4) / tthat?

Sea breezes are often encountereddoy9dgf-/z hj2s8hwk -l.p5q u;*kxq on sunny days at the shore of a large body of water. Explain in light of the fac- hh9k-wxy8zkp q 52uslddf*o;qj.g/ t that the temperature of the land rises more rapidly than that of the nearby water.

The floor of a house on a foundation under wzf6b w* )je:gx4dmw-:6 scsq)t.6opznf ; m okhich the air can flow is often cooler than a floor that rests directly on the ground (such as a f))4:pe zzm 6ms:btjfg dcqxk;ow6n* w.o 6s-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 therms pchispdju::-a84- ;hd n/u ig/wi l0ometer in the j:uch:an/;ulpg 8/d i0h iswid s--4pshade.

A premature baby in an incuw941gftlbo6o d2 tmk9nf.8cz bator can be dangerously cooled even when the air temperature in.c4okd6w9gf9lt2zft 1bnm 8o the incubator is warm. Explain.

Why is the liner of a.*im, c qwwes/j41fof thermos bottle silvered (Fig. 14–15), and why does it have a vacuum between its t i.4 c1o,w/qejs f*mfwwo walls?

Imagine you have a wall that is dyc le lyq( q3bom0r+2d/+9n gvery well insulated — it has a very high thermal res3yl0n/q oq29 clmebr++(dgy distance, $R_1$ 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) venpo5tty4lwm 57wvp 99etilation around edges; (2) through the frampm9wtevy4w57t 9lop5 e, 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 in the Sun absorbs more heat +p qjzz9,887wl7 yg.z ciawzt than a piece of shiny metal. Yet the wood feels less hot than tyz p879q.8izwtjzgw +c 7z l,ahe metal when you pick it up. Explain.

The Earth cools off at night much mo6p ki hcbozb3hvq,b69 *e(qc ;re quickly when the weather is clear than when(q i6c3k qhpo6bcb;,*9v hb ez cloudy. Why?

An “emergency blanket” is a thin shiny (metal coated) plast chb, ecgwz0w648x5;nc wej2j ic foil. Explain how it cjw;cc84n, zx25c6gj e e0ww bhan help to keep an immobile person warm.

Explain why cities situat3 toi; wmqit3-3 h*ynqed by the ocean tend to have less extreme temperatures thay -n33t;* hqmqwt 3iion inland cities at the same latitude.

  How much heat (in joules) is required to raise the temperature of3ohi: ka0h ci5sgrnr )bl2-j0 30.0 kg of waterh gjikr0las:5 b-r co0 23)inh from 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 initiallyeax e;k 9(*lpeli1k4i at 10.1p4*ek;li(ae xlie k 90 $^{\circ} C$ ?    $^{\circ} C$

  An average active person consumes ab5 6kn) e/-uubr2gcix2g b6 dqjout 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 (Btv rd s.*ximv rhqe.1fp*e81g4u) is a unit of heat in the British system of units. One d4* ev *rveg. px81f.qhrsim1 Btu is defined as the heat needed to raise 1 lb of water by 1 F $^{\circ} $ . Show that
1Btu = 0.252kcal=1055J

  A water heater can gdk 7 .duj t4w,y14vnv .5(fnfyz4n3dvyju dz)enerate $32,000\,kJ/h$ 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 long it will tpygg x; ow,t:jr9e hp )):d)vxx;l 5voake to heat a cup of soup (assume this is 250 mL of water) from p;oo: )x)x,y9tx ep; ggrjdvwl 5):hv 20$^{\circ} C$ to 60$^{\circ} C$ .    min

  How many kilocalories are generated when the brakes are used to bring a 12009.zbwmi)p+ 8yyoq r 2jvsf ozf7x37 8/rd yy.s-kg car to rest from a sv)fy.q+ym bzrs7jw9do8oy i3 2pr/fx.7s 8zypeed of $95\,km/h$ ?    kcal

  An automobile cooling system holds 16 L of water. How much heat does it absorb pvykaly-r+ot2; -;e pif its temperature +rv;p y -loetpy-2;karises from 20$^{\circ}C $ to 90$^{\circ} C$?    $ \times10^{ 6}\,J$

  What is the specific heat of a metal s4b3:o6h js3btw j.ic xubstance if 135 kJ of heat is needed to raise 5.1 kg of the metal from 1jibh. two3x34sjc6:b 8.0$^{\circ}C $ to 31.5$^{\circ} C$ ?    $J/kg\cdot\,C^{\circ} $

  Samples of copper, aluminum, and water experience the same tempera .q4 e(cf- 3yeo7iiq) fre-vibture rise when they abso i rfocieef -qbq(i7e4)y 3.-vrb the same amount of heat. What is the ratio of their masses? [Hint: See Table 14–1.]$m_{Cu}$ : $m_{Al}$ : $m_{H_2O}$ =    :    :   

  A 35-g glass thermometx2rs o(vdq 7- qv8lwiny02 c4ber 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 equilibrin q8axt5 4he-jum temperature when a 245-g block of copper at 285$^{\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 enl 1,*d 8 pehvdg5ce+= $0.4\,kg$) 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 sy h(jwn5f, ky6ubstance is heated 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 coffeepot to bring to a boil 0.75+m8l liqgnv6 qx1 1t6w L of water initi 8v1g1qntw6 x+llq6mially 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 measure:0s-m ivap8 pfments. A 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 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 15is8afppv m -:0.0$^{\circ}C $ , and its temperature after ignition is 53.5$^{\circ} C$ .    Cal

  When a 290-g piece of iron at p;a10: mr8c-a1bid gd) s. sxz p8krky180$^{\circ} C$ 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 /q1y xz*5ek(eys v )i4tem3 vnd(vmy4 a hammer has a 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 abt3i oez +6n.ui-u8zis defined as the amount of heat needed to raise its+- eio n3t.8ib6zua uz temperature 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 is initiallx23 oq7xtv:tz7ov-5 0nb sce my at 20$^{\circ} C$?    $ \times10^{6 }\,J$

  A 0.095-kg aluminium spher;vux c)j/k7ad4 b8xcje is dropped from the roof of a 45-m-high building. If 65% of the thermal energy produced when it hits the7j)vkx8d j;/ a4cc bux ground is absorbed by the sphere, what is its temperature increase?    $C^{\circ}$

  During exercise, a person may give ofjg/7pqmb60ef +jn zo4 f 180 kcal of heat in 30 min by evaporation of water from the skin. How much w/mfq +g jjpbno06 ze47ater 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 po rah.)n h4j5ewint is dropped into an insulated container of liquid nitrogen. How much nitrogen evaporates ij .ra5nw) heh4f 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 takenc 2m4qf(a(dxn from the freezer at -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 con8 6zs m)p hvzi:o ml1io-05aiptains 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, a bicyclist consumes 8.0 L of water overb jpc6v7b )va;0 4earb the span of four hours. Making the approximation that all of the cyclist’s energy v ) 7ajpeab06b4b ;rcvgoes 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 does go to heat, so our approximation is not far off.)    kcal

  What mass of steam ahkyb5u, 7)sza: uj.9oll cgo +sc*o p3t 100$^{\circ} C$ 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 me/+ehsfr/j4;do,kuxw rcury 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 travelin6pn1+x5e lk-drc3 fjo2go n2rg 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-skaterk)c)ezeq 5 +m1*zfdz5trpc;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 i1vyf tu/x:/v.m+tsc lead bullet that was stopped in a doorframe apparently melted completely on impact. Assuming the bullet was fired at room temperature i1c ms:tty./fx/+vuv(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 at 4fbx tdj;t6t v:q x)n4/60$^{\circ} C$ , 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 Examprk/uog,7 o;7p9ei srs +a :bumle 14–10, assuming that th7ri+rgo umspb aeso/:,;9k u7ere are strong gusty winds and the external temperature is -5$^{\circ} C$   $ \times10^{4 }$ W

  (a) How much power is radiatef4n4/ouczl /n d 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 skin. Suppose 200 W of heat flowsumrr)gv akuz +ea3.a2k-db* e// p 7ig by conduction from the blood capillaries beneath the skin t)bv2auizpu/r7 ark e . gg/ ke-+ma*d3o 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 mt0j ay*tk 0g5g per side, share a 12-cm-thick brick wall. Because of a number of 100-W lightbulbs in one room, the air is 50t0ktgay gj* 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 block 06 f4:ow1xli(ku 2tjxbdgk.w 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 lypu0 9pw6st 6same length and cross-sectional area are attached end to end (Fig. 14–18). The copper end is placep6puw 6 yts09ld 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, estig 39/- feyvff7yyrr q+2xct 1imate the rate at which the whole Earth receives enevrrqt-f1 + fg9x7ife2y /ycy3rgy 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 through abswx+2i d8kr/g4 x8gh glass bulb that has a radius of 3.0 cm and is 1.0 mm thick. What is the difference in tempg2gri88s/h4 wk x+ xdberature between the inner and outer surfaces of the glass?   $^{\circ}C $

  Suppose the insulating qualities ofsfprftbc.t f46 / yy+; the wall of a house come mainly from a 4.0-in. layer of brick and 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 ib ysrf4+ ;/t.f6f pycts $240ft^2$ and the temperature difference across it is 12 $F^{\circ} $?    Btu/h

A double-glazed window has two panes of glass separatedha17 ma,bc*ij by an air space, Fig. 14–20. (a) Show that the ratec7am,*1 bjh ia of heat flow through 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 ta:e8w9zk/ j/2ty yr mejke 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 conngo i3 /(bmmgn2t4 yq obl871w ,b5ijdtains about 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 contaib5apf8f+ox/ t ned in the 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 t5po f8 bf+/xawater for this estimate.)    $ \times10^{ 15}\,J$

  A 15-g lead bullet is tested by firing it into a fixed block of wood with rh)6d7l02jl qf. t lxp 4an;adm1 nm*ma mass of 1.05 kg. The block and imbedded bullet together absorb all the heat generated. After thermal equilibrium has been reached, the system )6h.tfan mrx njlmd lda 4;l 0pq21m7*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 Sun, asyj6c vg(5adw,momcq7d1 ., y k3 thko2suming it to be a perfect emi( ,5cdm, d7ow.cjg2kt6ym3kv1a o qyhtter 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 gen+;-bukbft n; gq+efs 2erate $200kcal/h$ 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 cliff and falls a vertical hen*p4l,k7) iko hzar ixx+/diqw)h:x-ight of 140 m before striking the ground. Estimaik-h /hdir,)axi+ o:wxzlx) *74k qpn te 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 dropped intob +kr+v jclk1gvlzzsg n/ .w+;8lbz/ 7 a 2.5-L insulated pail of water initially at 20..bwlvb; g+vzg7l/lnsrz8++ / kjzc k10$^{\circ} C$. 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 gooj9f g gdrg.o5mvj 6if;m2d8z7se down jacket 3.5 cm thick with total surface areagjogm6v2 zjgfm9 d7d.8;rif5 $1.2\,m^2$ 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 haec9 rh62)ikw4qxgh h9msr12 as an average 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 interior of the /kpp+odrp bjh :6qbg- -i*di: body to the surface. Assume that the thickness of tissue is 4.0 cm, thatdb+ bprdj:-- gih pk: 6poi*q/ 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 wallxnmn m 8 : msanhlu*d0px7)(f j:a2.dxs 17.5 cm thick (assume conductivity of air) and a.n*xlpx fdnm2:(s)0 dh mua7m8 :njxa rea $410\,m^2$ 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 tr t.8muvcir tu64-lj2b aveling 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, take into account radiation fr3g 6nn 5/ tk*vowqnvn2om the leaf to calculate how much water must be transpired (evaporated) by the leaf per hour otqnn/26n3* n vwvg5kto maintain a temperature of 35$^{\circ} C$.    g/h

  An iron meteorite melts when it enters the Earth’s atmosphere. If its initt t+*lqxfn8 b:ial temperatt fn+8t*bqxl: ure 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 2 , kt+l-dsw2c k/qfft ob,is5crust 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), two people hieo 1mvl uq7u,:t qga7,w8hp *it a soft rubber ball at a wall until they are about to drop due to dehydration and exhaustion. Assulqgu :1w u*iat7 ev p7,hq8,mome 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 of8u;iy988 ibyl8k y ngh ice at 0$^{\circ} C$ and steam at 100$^{\circ}C $ are mixed together?

  In a cold environment,gi/ohni2 b:kri2h)jab d2 ))c a person can lose heat by conduction and radiation at a rate of about 200 W. Estimate how long it would take foni)b) )c 2garj:hkdbo/2 2hiir 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, then 0bn8f oorbvnc;,( 5rre is “no hot water” left in the 50-gal (185-L) water( frnno , nv;cb85orb0 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 surface of ,x0,n cb7w mkfa 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.    $^{\circ} C$