What happens to the work donee+j-po9yw xa uft c .nvr;xnq7/n//s3 when a jar of orange juice is vigorously shaken?

When a hot object warms a cooler object, does temperature flow between)o-j6zth-r2wk y 9 mg5a)mg1 lg( fq-zy8fran them? Are the tezg (lh))r-1 r-jmna8 5wgay 6 omf ytg29qkzf-mperature changes of the two objects equal?

(a) If two objects of ri5ur)gv t d9o;o;1ffhz)2 ajdifferent temperatures are placed 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 flow even if the internal energies of t2vziff 9ro;o ha1 rdg j;)t)u5he two objects are the same? Explain.

In warm regions where tr-;ye,mf3x h ywopical plants grow but the temperature may drop below freezing a few times in the winteh -xf,y3;wyem r, the destruction 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 fact makes water: l2mm0 -evrdb(0mylu particularly good for heating systb(yu d m02 0v:erm-lmlems (that is, hot-water radiators).

Why does water in a metal canteen s sv p88nrh0umfrae y;s(y/)v(tay cooler if the cloth jacket surrounding the canteerv; )r(sh (amy8en8s/0y vupf n is kept moist?

Explain why burns caused by steam on the skin are often more severe than burnfc g)cbh0y quf6 ); 6swbz0n2as caused;u))z 0c fy0 n6bfh casgb2wq6 by water at 100 $^{\circ} C$ .

Explain why water cools (its temperature drops) when it evaporates, using the lwqu0bkz*t vm : a65g7lm/1( *days bp9,xsh qconcepts of latent heat and internal enbma kg5hus/t bdq6xl*wvzy: qm 0 p,s1(al7*9ergy.

Will potatoes cook faster if the3bhgdf4 a f-o8 gnfn6* water is boiling faster?

Does an ordinary electric fan cool th3miofok :39 kae air? Why or why not? If not, why use it?

Very high in the Earth’s atmosphere, the temit2p yfhh7i;4- ey9seperature can be 700 $^{\circ} C$ . Yet an animal there would freeze to death rather than roast. Explain.

Explorers on failed Arctic expeditions have mh.69x6ckow u:ryy. vsurvived by covering themselves with snow. u9.wx:y. ck r hmy66ovWhy would they do that?

Why is wet sand at the beach cooler to walk on tynh an9u(br (z6z c7*uhan dry sand?

If you hear that an o:ar +/wtgu--1u l1bbyhjj ,pxvj,1ewbject has “high heat content,” does that mean that its temperature is high? Ex-jy1u:tgj p+hwb ev11xur ,ab,wjl /-plain.

When hot-air furnaces are used to heat a;f q fcof:uka z*m4kp3q7z4 os hn;-6j house, why is it important that there be a vent for air to return to the furnace? What happens if th os; -kacz*fo;pz4 k:qmq6f73j4fuhnis vent is blocked by a bookcase?

Ceiling fans are some6c 8az5ttiqh6bd) b :dtimes reversible, so that they drive the air down in one season and pull it up in another seaso:bi zhq 586bt6datc d)n. Which way should you set the fan for summer? For winter?

Down sleeping bags and parkas are often specified as so many inches oc ci:z, v;1e8u5em nomr centimeters of loft, the actual thicknee z; 1mu,c5 ncmo:iev8ss of the garment when it is fluffed up. Explain.

Microprocessor chips have a “heat sink” glued on top gt(ur7mq vm31. myu 6dthat looks like a series of fins. Why is it shaped lik(6 yu1u qgvr.3 7tdmmme that?

Sea breezes are often encountered on sunn+kwq) q 0e;)wqts2ohzo n nm2.y days 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)okh0nt; w 2q+) .z2wqq osmen that of the nearby water.

The floor of a house on dbs9qf 31hen 4a foundation under which the air can flow is often cooler than a floor that rests directly h1d snf3 9be4qon the ground (such 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 temperature readings are always ab*cz: *bahzx: ;kby;taken with the thermometer in the sha:hbbaxkzcb *;a*; z:y de.

A premature baby in an incubator can be dangerously cooled ie3eo 7 m lo8et,i.4beeven when the air temperature in th. t3ioee eeim4l o7,b8e incubator is warm. Explain.

Why is the liner of a thermos bottle silvered (Fig. 14–15), and sv9s1d kcf;k8 h hlc:6n0t;scwhy does it havec6cs19ndk80stlhv :;c kf ;hs a vacuum between its two walls?

Imagine you have a wall that is very well x-/qk* jw aesci)l,5 xrh9(gkinsulated — it has a very high thermal resista5 k(al- *cj/) rqxeh xw9s,kignce, $R_1$ 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 piysfju(// 3yn fpztru ; ph7:*bo;de*rocesses: (1) 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) the mechanism(s): conduction, convection, or radiation? (b) Heavy curtains reduce which of / tr7fy 3/uzpbdih o*fp;*:ns ;yjue(these heat losses? Explain in detail.

A piece of wood lying in the Sun absorbs more heat than a piece q kb6qw4 m0(qsof shiny metal. Yet the wood feels less hot than the metal when you pick it up. Expl4 b0qkswmq(6q ain.

The Earth cools off at night much more quickly when the weather is cm(gxep 76 sg22v9 .w- botbvng/ fkdb9lear than when cloudy. Wb t/bwvse2 n ( odmb97fvpg-6kgg.x92 hy?

An “emergency blanket” is a thin shiny (me62 y0f gsaw2xktal coated) plastic foil. Explain how it can help to w02x6agfs ky2 keep an immobile person warm.

Explain why cities situated by the ocean tend to have lew/yv/du +r )rqss extreme temperatures than inland cities at the sr /v)w+yu/rdq ame latitude.

  How much heat (in joules) is required to raise the temperatuh x7o/r-ndd0b t,dr* bre of 30.0 kg of waterdx*0 bo-/trbdn7d r, h from 15 $^{\circ} C$ to 95 $^{\circ} C$ ?    $ \times10^{7 }\,J$

  To what temperature will 7700 J ofant49 n8zs s1ghc ;6gdlz-*pp heat raise 3.0 kg of water that is initially at 1- 1 l94s8cpp;hzs *6adgztnng0.0 $^{\circ} C$ ?    $^{\circ} C$

  An average active person cons2a glc u)lv4f4umes 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 (p3l zbx lke.uj)5-z d4Btu) is a unit of heat in the British system of units. One Btu is defined as the heat needed to raise 1 lb ol - z3j5bep.du)xz4l kf water by 1 F $^{\circ} $ . Show that
1Btu = 0.252kcal=1055J

  A water heater can generabol* 5njtm0co ,z/ i;hte $32,000\,kJ/h$ How much water can it heat from 15 $^{\circ} C$ to 50 $^{\circ} C$ per hour?    kg/h

  A small immersion heater is rated 6c84he+(g-l n k+hwer vjvhk;at 350 W. Estimate how long it will take to heat a cup of soup (assume this is 250 mL of water6vew4 v;h (h+ lkhgc+e nk8r-j) from 20$^{\circ} C$ to 60$^{\circ} C$ .    min

  How many kilocalories arot j(b/s:j p/d-gp5xbe generated when the brakes are used to bring a 1200-kg car to rest from a spe - jds/5g jpb/(otb:xped of $95\,km/h$ ?    kcal

  An automobile cooling system holds 16 L of water. How much heat docfwcj 4+5s nco lrl23.k/dk 8hes it absorb if its tempelhcf42k .3ork nw5d+ scj8l/crature 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 f/ifge: - z474oscn ihheat is needed to raise 5 si4nc:o-7gizf/ feh 4.1 kg of the metal from 18.0$^{\circ}C $ to 31.5$^{\circ} C$ ?    $J/kg\cdot\,C^{\circ} $

  Samples of copper, aluminum, t44*1gb t:qfvuy+ ukaand water experience the same temperature rise when they abs * :ft4bkauugt1v4qy+orb 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 thermometer reqd eiv1)o85pbzz( y c:ads 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 cr.-g ,raqb0kqg: a;qd opper 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 (m,rbw:q i0h4b xass = $0.4\,kg$) 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 su)9*7u e,cerd2h gsouz bstance 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 L of watrbf w6w7 4+vd7g:kqtb er initially4w fq b:7w6bkv7drg t+ 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 can9hli +a:zz4d gdy from the following measurements. 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 ca+g9zzih4l:d up 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 iron ag4ldr h-ra3,(bht,f i5jhmi5kppe53t 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 hammerrp(fn:x64duz 4 iqi a zg8n /6*rx8ixo 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 is defined as the amount ofb9xx8m 4mdi,ty 5ou-ego5m 0g heat needed to raise its temperaturyou0t-,5 xd mogbem859gi4 x me 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 mef-ax+ -k/(dbd xiqq h*lt 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 building. I7lmpleu 3k p;m08qf (af 65% of the thermal energy produced when it hits the ground is absorbed by thepkuap l(ql7em3;8 mf 0 sphere, what is its temperature increase?    $C^{\circ}$

  During exercise, a person may give off 180 kcal of heat in 30 mi:l :shc7nav j8n+pxdi+sc(e -n by evaporation of water from the skin.:dp:(nsl7n-cihja8cxe+s+ v 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 pg;3qexler z 9;oint is dropped into an insulated container of liquid nitrogen. How much nitrogen evaporates if it is at its boiling point of 77 K and zl3g9er;; q xehas 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 9w qk(*lvn6e -cwiin hv/v j8*k- fq6athe 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 may( 2cesibd 91 tnpi4g/ss 230 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, a bicyclist consumes 8.)u5seu3o9 bvyfil 3-p 0 L of water over the span of four hours. Making the approximation that all o)p3 e vifuy5l9u3 -obsf 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 does go to heat, so our approximation is not far off.)    kcal

  What mass of steam at 100q.nx0)x k1isem0cp/t( e*za e $^{\circ} C$ 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 mercurd,2 t4oxef4bf(cy.v k y 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 traveling ae i5(x56 gibnut $250\,m/s$ 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 moving atz k0()-vwytbd $6.4\,m/s$ 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 mqs9wh-ni-rhyyi/d- g34x. dthe 8.2-g lead bullet that was stopped in a doorframe apparently melted completely on impact. Assuming the bullet was fired at room temperatur/ d4xygm.d-ihiyn39w h s-qr-e (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 dv la- nu cjp01j ynjo73jp6*;*i xqfy9iameter 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 ofub ai b6qo/*/tii6z uve3avmm38 16fk heat flow by conduction in Example 14–10, assuming that there are strong gusty winds and the external temperabmq38u au1/ei6b6 ovtkvimaz/* 63fi ture is -5$^{\circ} C$   $ \times10^{4 }$ W

  (a) How much power is radiated by a tungsten sphere (emissivilydr35 2s-l/ 3vy xa2:rzoooity $e\,=\,0.35$) 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. Supposhhh5ydel2eu8/ ze /on 4p/ 7tfe 200 W of heat flows by conduction from the blood capillaries beneath the skin to the body’s surface ard e/7 4nuhz8t/oph2hl5ey/ efea 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-cm6ks 215rpf7 xljr zk-ujf0;kr-thick brick wall. Because of a number of 100-W lightbk rp1k5;jr2r7 z 0lksuffx-6julbs 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 block of ice a9efsgermp:7( -;qy jut 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 rf44 :3hs xtyy5 y:qw;jlbdly+ od of the same length and cross-sectional area are attached end to end (Fig.sd3yy x:fylq ;5t4 lj +:whby4 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 Eart5uie: t;imo3akrjepo78h;g6 h receives energy from the Sun. 8pm 6ht3ero7 u ii;jka geo5;:    $ \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 elg q omnrn1t) fi8x54pz(-v595 W of heat, which is dissipated through a glass bulb that has a radius of 3.0 cm and is 1.0 mm thick. What is the difference in temperature betwenlp- e(vri)8mzfo5nq1gx54 t en the inner and outer surfaces of the glass?   $^{\circ}C $

  Suppose the insulatingj2te g/xymp4; qualities of 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 tott ;2xeg/m4pj yal 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 tw lg/+v9. qkw o.tup*8rkrs8lgo panes of glass separated by an air space, Fig. 14–20. (a) Show that the rate+* pvl.g9tuk8rsq.lw r/ go8k 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 take 11j/j mj3is ts75.0 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 about,pc4ayo zl 9fgeve: *u3 ,u tc3vf*ybylq*h-; 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:(c 6cvo r 1e9mbx8yyj 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 omy 18 ojyv(cc9brx 6e:cean water as pure water for this estimate.)    $ \times10^{ 15}\,J$

  A 15-g lead bullet is tested by firing it into a akisfv( ux t:b. r;;/nfixed block of wood with a mass of 1.05 kg. The block and imbedded bullet together absorb all: ni;;vrk(baf/ xu.ts 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 radiatekq) xsk21 s+o :s-doi7i;. gu2hyas kdmn; vi,d into space by the Sun, assuming it to be a perfect emitter 1qk.2a;;xo do-i+d:s ,2nvs kusskiigym )7h 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 mazws dw0hbqci9mx8v t y3bt5).;mq w 59y 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 off the top of a cliff and falls a vex, dxel3c,q-8jg c r*crtical height of 140 m before striking the ground. Estimate the temperature rise jce8gdr3x x,,q c*-c lof the rock if 50% of the heat generated remains in the rock.    $C^{\circ} $

  A 2.3-kg lead ball is dropped into a 2.5-;iem1+cms jzbhejop 8 +k2:: xm tc71gL insulated pail of water initially at 20.0 mxbmj js1 eot2ek7ph:c iz;+c+1m8g:$^{\circ} C$. 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 sqxi.e0 0geq/zdud cdj0;+i2 surface area i0j0;egc2.d/x0qz + didus eq$1.2\,m^2$ 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 of about 8v:, rnbwjc 6n$950\,kcal/h$ 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 -jwjmgi1.zg ul: qrho.r(d 0: of the body to the surface. .u wr10 rmg(jz:gq.o:j-i hdlAssume 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 (a9bphv j 6gf41ussume conductivity of air) and area j1pvgh46f9ub $410\,m^2$ 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 aussb.(n 4n rjejy gh0(v9f1i/. h+gz ot $220\,m/s$ 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, tak g,/mfm)m4t4 *um lynue into account radiation from the leaf to calculate how much water musym) gu/4f4*nmt,ml mut 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 atmospherl 8dgphdh k qi+8*)v1ie. If its initial temperature was vl)d + hd1ih8pqk8g*i-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 increases about y bh3;eo *yo +z24nvkn1.0 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 hit a soft rubbes0zm kryb31w;4q5im hr ball at a wall until theh1 ; m0 wb3iqmr5ks4yzy 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 ze*rhsq qd0 hr(2) z,hresult when equal masses of ice at 0$^{\circ} C$ and steam at 100$^{\circ}C $ are mixed together?

  In a cold environment, a+,*0nvtzp1 fun-zpsl person can 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 fromv z,z s+un0n-1tlfp*p 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 dishwashingayj,1+ab z61 ybr5yv7 vu pr*l, there is “no hot water” left in the 50-gal (185-L) water heater. This suggests that the tank has* jz+6uvrap511yb a byv, 7rly 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 q ivwzf;*5 rs7ia9k2d60-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.    $^{\circ} C$