What happens to the work done when a jar of orange juiclb8n; / z fqf7(( n3aasrhg-sle is vigorously shaken?

When a hot object warms a cooler objeau7tbnr(((ca1h ro n.jri4 ; rct, does temperature flow between them? Are the temb7hc(r o41(.;ar (jrtarnuniperature changes of the two objects equal?

(a) If two objects of different temperatures 9j 7mv:z9 zjyxrvch0 7nx0;a dare placed in contact, will heat naturally flow from the object with higher internal energy to the object with lower internal energy? (b) Is it pos 0;jd:xv9cj amx0zzn h7yv97 rsible for heat to flow even if the internal energies of the two objects are the same? Explain.

In warm regions where troy b4;peiip jy0j(5. zjpical plants grow but the temperature may drop below freezing a few times in the winter, the destruction of sensitive plants due to freezing can be reduced by watering them in40 jyjjb(5p;iz e yip. the evening. Explain.

The specific heat of water is quite large. Explain wh o-k y((hvwki w5hz,i6y this fact makes water particularly good for heating systems (kwo 6-(,k iw(5hvzi hythat is, hot-water radiators).

Why does water in a metal canteen stay cooler if the cloth jacket surrounding t6x 8 smjrg1/wc:im +eu)3fmibhue+mi)6w8 cmx ji s:m3g r1/fbe canteen is kept moist?

Explain why burns caused by steam on the skin are often more severe than51d0t+nu 2 k bulaqxh; burns cause1dl uta2qk; n50bh +uxd by water at 100 $^{\circ} C$ .

Explain why water cools (its temperature r-cbllzv6. l7 drops) when it evaporates, using the concept 6zv.b-7lrl cls of latent heat and internal energy.

Will potatoes cook faster if the water is boiling fast*ikxo, 31mg dfer?

Does an ordinary electric fan cool the air? Why or why not? If not, why us2-fhc r b-zm8gy0ut1 we it?

Very high in the Earth’s ayt(q 7s(kr +hytmosphere, 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 survived by covering themselk(w x lu54:v5hvawgh 8ves with a: x (vwwuh5gh8v54lk snow. Why would they do that?

Why is wet sand at the beach cooler to walk on than dr) r*tir9ax b( nfpajh. q1ll23y sand?

If you hear that an object has “high heat content,” does that mean lsq8x /5+-i-r6 pt7tk tjj12fqlwwlo that its tempera7oiwqxw1j6t+t qs j5 tl8 frl--/k 2lpture is high? Explain.

When hot-air furnaces are uses4ss 8 sd;- 9ku+rvywcrvl (8dg*v pt5d to heat a house, why is it important that there be a vent for air to return to the furnace?(*pws 4stsl-9vd ;8v5 csd+urvg 8kyr What happens if this vent is blocked by a bookcase?

Ceiling fans are sometimes revecm;/d1w( ukr: y,j y,9etnyeqrsible, so that they drive the air down in one season and pull it up in another season. Which way ,dm/9ey:yrcun y(t ;qew1 ,k jshould you set the fan for summer? For winter?

Down sleeping bags and parkas are often speu(c y7en2+nah( lu ud ,er7-aqcified as so many inches or centimeters of loft, the actual thicknessn2d+( -ceyu7nrulhe ua a7, (q of the garment when it is fluffed up. Explain.

Microprocessor chips have a “heattw/9j/ vfyt. q sink” glued on top that looks like a series of fins. Why is it shaped /wf y/jtq. 9tvlike that?

Sea breezes are oftenf ogl:nx*u 3 0mj3bip5 encountered on sunny days at the shore of a large body of water. Explain in light of the fact that the temperature of the land rises :u mj*3op l35bx0gnfi more rapidly than that of the nearby water.

The floor of a house :) ulxdd pdadn-cm +9h /dbs,3on a foundation under which the air can flow is often cooler than a floor that rests directly on the ground (such as a concrete slab foundatiousddbxld /c3 hp,dd+ :-n)9ma n). Explain.

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

Explain why air temperatur f(jz6:daaus8dnp, j8gt2 vlo6 -uuf4e readings are always taken with the thermometer in the shadegz8ua -2vf:s8una,6p jddujf(o l t46.

A premature baby in an incubator can be dangerously ,ydig+)e7tiip 9dn n*lcv0 f +rxoi +)cooled even when the air temperature in t lg)+f + dv i+7x9)onrdpiii0 ,e*tcnyhe incubator is warm. Explain.

Why is the liner of a therm;grlgx 77)+c3r+g-c9zix mi nwq)nm a os bottle silvered (Fig. 14–15), and why does it have a vacuum bet9cngc -)7r+a gi g3n);+m ixmr qzxlw7ween its two walls?

Imagine you have a wall th8ja9 o/vdg tipco59( mat is very well insulated — it has a very high thermal v5i/cgjpoao9 9md 8(tresistance, $R_1$ 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 prgg5j;nmdzo z td9x)u1 iex /y*--1nam ocesses: (1) ventilation around edges; (2) through the frame, particularly if it is metal; (3) through the gd xy*gx )9 o5z;nnuetdi1z1 /-ag- jmmlass 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 than a piec 5owioceu8j .)e of shiny metal. Yet the wood feels less hot than tcoj8e.o wu i)5he metal when you pick it up. Explain.

The Earth cools off at night much more36 4odfl+9v 0ttyj yqr quickly when the weather is clear than whe tryo63f0lv9+q4tdj yn cloudy. Why?

An “emergency blanket” is a thin shiny (mc+/+f;p hgob6bq / mbnfn8+subi7ni1etal coated) plastic foil. Explain how it can help to keep an immobile persof;n +7bc/gim 6qu+n phb sb+ fbon/81in warm.

Explain why cities situated by the ocean tend to have less ext7-k o;b o2zcopyu74doreme temperatures than inland cicduk77;- obpz yo24ooties at the same latitude.

  How much heat (in joules) is required to raise the temperature of 30.0 kg o bry58(lx+xs7 k2l 1zjt xfm03sja c1if water fr y k17l5xicsfj18a (sjtzl32m+x xrb0 om 15 $^{\circ} C$ to 95 $^{\circ} C$ ?    $ \times10^{7 }\,J$

  To what temperature will 7700 J of heat raise 3.0 kg of water tha1+isf t j.:m*crbirh6 5 /nvn)ixu( jwt is initially at : +rj t( u6xmni5ch1wvf/b*ijsri.n ) 10.0 $^{\circ} C$ ?    $^{\circ} C$

  An average active person nk/qcx d 5hln)1;s7hi 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 heat in the Britishsmrlb, 9 .dv7n system of units. One Btu is defined as the heat needed to raise n7.vr sdml9 ,b1 lb of water by 1 F $^{\circ} $ . Show that
1Btu = 0.252kcal=1055J

  A water heater can gegh0fnp3:*k*d aicy q +6o8hj onerate $32,000\,kJ/h$ 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 352 zs6vu1g bvf7/ncz( c0 W. Estimate how long it will take to heat a cup fczc1v b6 g7uv2/ (snzof soup (assume this is 250 mL of water) from 20$^{\circ} C$ to 60$^{\circ} C$ .    min

  How many kilocalories are generated when the brakes are use ,z qiwo;/ h.gkxxwe7v7el.*hg28 zpxd to bring a 1200-kg car to rest from 7gl,e 2w;ghqx.pi8 hk o7v/*exzw.xz a speed of $95\,km/h$ ?    kcal

  An automobile cooling system holds 16 Lh4,*gtgk/qydst om9z 3j;x. a of water. How much heat does it absorb if its te k y j*o3as49h/zdgtgm.xq;t,mperature rises from 20$^{\circ}C $ to 90$^{\circ} C$?    $ \times10^{ 6}\,J$

  What is the specific heat of mxwyg; /63s+y pxd4jga metal substance if 135 kJ of heat is needed to raise 5.1 kg of the metal from 3 g ;4xsxpyy6+m/jdwg18.0$^{\circ}C $ to 31.5$^{\circ} C$ ?    $J/kg\cdot\,C^{\circ} $

  Samples of copper, aluminum, and water ex r60ink004dizub v1kh07+yx6yz lp wdperience the same temperature rise when they absorb txhn uzd0kw7vlyi6061ipd +0r zb0 y4khe 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 thermomet5:mr39ts unm jer reads 21.6$^{\circ} C$ before it is placed in 135 mL of water. When the water and thermometer come to equilibrium, the thermometer reads 39.2$^{\circ} C$ . What was the original temperature of the water?$T_{iH_2O}$ =    $^{\circ}C $

  What will be the equilibrium temperat 5b4 gt*94te8nr,qee ljm pg-fure 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 zw e );zbje):)jh w1ef(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 heated t5dlb1(u lpfe9v4zrd03.jj zxo 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 eth5(5 .h3o k )nntg -o3dfnracoffeepot to bring to a boil 0.75 L of water initially afng5.e nh o5 ht(rd)t3kn-3 oat 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 okh 3t9 thx*cp:f 75 g of candy from the following measurements. A 15-g sample of the candy is allowed to dry before putting it in a bomb calorimeter. Thh9x tt* h3k:cpe 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 ofs g0z8 ih/r2aa9i2uaq 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 h+ 3(esmar 5rdf oiw-w)as 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 of heat needed e 0ez1c3by8 qbwb*r51x -nsap,p njh /to raeppjaz1b* y/853enbc1hb -sxn 0wrq, ise its 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 thatw:16g v*qaiz u:w3vcb is initially at 20$^{\circ} C$?    $ \times10^{6 }\,J$

  A 0.095-kg aluminium sphere is dropped from the roof of 7 mf5 dfx:i* 6b(oauzoa 45-m-high building. If 65% of the thermal energy produced when it hits the ground is absorbed by th6o:ofd afu75izm* (xbe sphere, what is its temperature increase?    $C^{\circ}$

  During exercise, a person may give k 4mjf/+o ms+a0n7yzqoff 180 kcal of heat in 30 min by evaporation of water from the skin. How muy smj/ok0 7+afzmn+q4ch 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 or exrz9f,bp,-;l qw.k f liquid nitrogen. How much nitrogen evaporates if it is at its boiling point of 77 K and has a .l e;z9rpf,r ,qx-b wklatent 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 kqd/70g d 6 . ftkqxk3he-e6nrdqu1;kfreezer 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 contains 830 kfy16p s3o 5burg 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 cons)zvi 1v s5)s2iy:ecvsd3j(jj umes 8.0 L of water over the span of four hours. Making the approximation tyv35)v(j)i 1s:c2des zjjsiv hat all of the cyclist’s energy goes into evaporating this water as sweat, how much energy in kcal did the rider use during the ride? (Since the efficiency of the rider is only about 20%, most of the energy consumed does go to heat, so our approximation is not far off.)    kcal

  What mass of steam a7cje :b :3fbykt 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 xv vh pj3fe*3g6(vae/mercury 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 at yb o:a8s8:qt6hyacar,ps1 6a $250\,m/s$ 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 at :z*;8wt0/to*nja s leksh2cd $6.4\,m/s$ 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, thi:o xfo-,0 rvze forensic investigator notes that the 8.2-g lead bullet that wasxo-rv0of z i:, 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 diameter frr6c 1h3 n/k7fn:uw5ilu0 olof 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 Examzl 26u kw;1apople 14–10, assuming that there are strong gusty winds and the exter1z2;ku6ow al pnal temperature is -5$^{\circ} C$   $ \times10^{4 }$ W

  (a) How much power is radiated by a tungsten sphere (e1(9 fvo oux3znmissivity $e\,=\,0.35$) 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 flow x. fiav,xj jwv-e o7(k-3ucx:vak .+is by conduction from the blood capillaries beneath the skin to the body’s surface area of.3ex7 v: i-uxfak+v-ixjv ock(wa,j. $1.5\,m^2$ 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 5ne ask5g4q3f wall. Because o5kqe35 ngaf s4f a number of 100-W lightbulbs in one room, the air is at 30$^{\circ} C$, while in the other room it is at 10$^{\circ}C $. How many of the 100-W bulbs are needed to maintain the temperature difference across the wall?    bulbs

  How long does it take the Sun to melt a block of ice;njg2l4e pm( a 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 a+ m2zl +dx7wmsywm+ .4;z gwoynd cross-sectional area are attach7.o zmwxgs+2wzy wl d+;y+mm4ed end to end (Fig. 14–18). The copper end is placed in a furnace maintained at a constant temperature of 250$^{\circ} C$. The aluminum end is placed in an ice bath held at constant temperature of 0.0$^{\circ} C$ . Calculate the temperature at the point where the two rods are joined.    $^{\circ} C$

  (a) Using the solar constant, estimate the rate at which the whole Earth recq z/amk*xo;s;,f proo08t)x; po9t oreives orrto,k8m o;9q*xpp;o;x0ft/sz a) o energy 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 0bfu mm9 rt:g ud/ eqsdpp:x*gzi):2g/2ztu3is dissipated through a glass bulb that has a radius of 3.0 cm and is 1.0 mm thickmp : i3:z s2/td0b: u gg/rmu)fexqzu*9g2ptd. What is the difference in temperature between the inner and outer surfaces of the glass?   $^{\circ}C $

  Suppose the insulating qual)w f*m/uy0sc mities 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. 14–19u/ *y cfwm0)ms. 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 windor aume3t7ah ;8w has two panes of glass separated by an air space, Fig. 14–20. (a) Show that the rate of heat flow through such a window by conducte8a r3aut;hm7 ion 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 ta3r.em01hup at ek +(boke 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 about 0.20 kg of liquiq*,d2hcl khs/wyb 8 l; 3vecwhsch*:.d 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 therm g* e kurt0e* e;oy3m ;mjkzy-6d86fixal energy is contained 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. (A*8uke mk; rm*g 6eeioxf 6; j3y0-tzdypproximate the ocean water as pure water for this estimate.)    $ \times10^{ 15}\,J$

  A 15-g lead bullet is tested by firing it into a fixed block of wood wit)lni+h401v/ gisoo 29yk(hgh s zpr-sh a mass of 1.05 kg. The block and imbedded bullet together absorb all the heat generated. After therma/ gni ky4 soig p290 o+z-sv)hrhh1(sll 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 rx15w0a,(g j tn a8bmwmadiated into space by the Sun, assuming it to be a per 8 w0tjmn5ba 1w(gx,amfect 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 m35hkv3*.3lypbmb) ur kgiw8say 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 verticalyh5j5. i(4ta dqkkp 7o height of 140 m before striking the ground. Estimate the temperature rise of the rock if 50% of the heat generated rema(tdopak5y5j4kq hi. 7ins in the rock.    $C^{\circ} $

  A 2.3-kg lead ball is dropped into a 2.lc, 2z gowq ( rbw6dnd/7hr,q;5-L insulated pail of water initially at (7ch,z l; 6bd 2w,qgnrrqd/ow20.0$^{\circ} C$. 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 d.3 ubu7znjg7 9spy)m bown jacket 3.5 cm thick with total surface areanb3uyup .j7) msz97 bg $1.2\,m^2$ 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 avekgc xzc4r7:2/2v kmdz5 g9mftuq) s8d rage 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 i, hj,sm51bh/j k x9ogpnterior of the body to the surface. Assume that the thickness of tissue is 4.0 cm, that th msb/ghoxph5jj,,1k9 e 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 (assume conductivity of air) a8plqemoh s ayt 441ll*g*rg 50nd area l8lh5e1 ramls4 oqyp0 *g*tg4$410\,m^2$ 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 trab(ilwcr) f1r 0veling 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 from tjiuui6 n 02nr6he leaf to calculate how much water must be transun 6iriju0n6 2pired (evaporated) by the leaf per hour to maintain a temperature of 35$^{\circ} C$.    g/h

  An iron meteorite melts when it entersrbbutg g,vn 1i7t 7mni-:v00a the Earth’s atmosphere. If its initial temperature was1t g -nmbrva, t 7uiig70vn0:b -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 if8i +k,p k e*vtamch qhkr51,0ncreases 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 q8f*an6kd hv0 squash (Fig. 14–22), two people hit a soft rubber ball at a wall until they are about to drop due to dehydrat8a q06fd*k hvnion 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 finalfd ql)kw m 00plqla/;9-vepuzo 3z;y- result when equal masses of ice at 0$^{\circ} C$ and steam at 100$^{\circ}C $ are mixed together?

  In a cold environment, a person can lose heat r 4y)m7-g d -2hlrizjm(k5a gfby conduction and radiation at a rate of about 200 W. Estimate how long it woul5r zr(g)gma7 ihdfm2 y -jkl-4d 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 the 50-gaky na0j1 ,u-v(aepux7 l (185-L) water heater. This suggests that the tank has emptied and refilled with water at a-peuaxy 0u7jvnk,(1roughly 10$^{\circ} C$. (a) How much energy does it take to reheat the water to 50$^{\circ} C$? (b) How long would it take if the heater output is 9500 W?    s

  The temperature of the glass surface of a 60-Wsl 20t gr5k;x5mwuo1 t 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.    $^{\circ} C$