What happens to the work done when a jar of orange juice is vi5i4rm0,7ig w;d( uuji qcr9gj gorously shaken?

When a hot object warms a cooler object, doeo;f* vh h,1s p0ex2pbfs temperature flow between them? Are the temperature chaf2;sbpe0*hh,o v fx1pnges of the two objects equal?

(a) If two objects of different temperatures are placed in conty5 qqo*1o+)sa frdn :yact, 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 the* f:o+n1qro )qydys5 a two objects are the same? Explain.

In warm regions where tropical plants grow but f zph;tl,q;0fxy*on)the temperature may drop below freezing a few times in the winter, the;qn ,f )xoztylf;h*p0 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 watggn..d oz- )gder particularly good for heating systems o)-.d nz g.dgg(that is, hot-water radiators).

Why does water in a metal canteen stay cooler if the cloth (u o3i w/y2 2sacjnudpj(j9 t(jacket surrounding the cp cy9/d(tw2ou2j(jnas( 3 j iuanteen is kept moist?

Explain why burns caused by steam on the mdsb .w+drz42 skin are often more severe than burns caused by mz+s . dw2rbd4water at 100 $^{\circ} C$ .

Explain why water cools (its temperature drops) when it evaporates, uacbs 1+ua38cu sing the concepts of latent heat and internal abu s318+caucenergy.

Will potatoes cook faster if the water is boilinas4c) yuossq4 ujak9y7/.gy/vlc x) 7g faster?

Does an ordinary electric fan cool the air? Why or why not? If not,f l2- m 0.+rzve3e:mexdzb9ds why use it?

Very high in the Earth’s atmosphere, the temperature caxg9q85p nkj1x- 2/huqrl /zibn 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 themsele8 gxtm-0gq g./gd5irbyz/ya,v+ / wnves with snow. Why wdetvg,q /05 my/ g+bixg/ r8-awzyn.gould they do that?

Why is wet sand at the beach coolerwa,+d53fbhkmd 8c2 kw to walk on than dry sand?

If you hear that an object has “cpkr :k):fj6 x t5dfn(high heat content,” does that mean that its temperature is high? Expfc:(k5: j)pkt fxnrd6lain.

When hot-air furnaces are7*/.j fbnu*3e9i so+ts 4yj;kgvykno used to heat a house, why is it important that there be a vent for air ye7o4v3g;/*onjnk9yiu*bsfk.t j+s to return to the furnace? What happens if this vent is blocked by a bookcase?

Ceiling fans are sometimes reversible,lz 8b:8m: fhz t8kvet1d(xc x3 so that they drive the air down in one seasoncx8t1(v3 hzm:xz88le bfkdt: and pull it up in another season. Which way should you set the fan for summer? For winter?

Down sleeping bags and parkas are often specified a.7-j qms5aigia9dl-x u3 sr,xs so many inches or centimeters of loft, the actual3-msj s -.iaxaxql i5,ud97gr thickness of the garment when it is fluffed up. Explain.

Microprocessor chips have a “heat s48rsqmj+5 ni -vz5deoo;dhdbl.u j, 0ink” glued on top that looks like a series of finsvi 8reo-.dojn0s+jhqbd;u4 5m z dl ,5. Why is it shaped like that?

Sea breezes are often encountered on sunny ww)ra q4/1 tmcd/2jnbdays 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 that of th 1wwa r4tb)/n /j2qmdce nearby water.

The floor of a house on a foundation( /yoat 53yhdm ujdr)t96s7aa under which the air can flow is often cooler than a floor that rests directly on the grodyst) ayt36d(7 5ao9mjr/a h uund (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 taken with c,zajhe7f re:t(7 ry;the thermometer in the shade.,z7rry;fjta c(7hee :

A premature baby in an incubator can be dangerously cooled4g6*+h7obw fzf yneba cb v;3+ even when the air temperature infof;e++g* 6bb7hbvanz 34y wc the incubator is warm. Explain.

Why is the liner of a thermos t bu76hzv2syek7 e (0qbottle silvered (Fig. 14–15), and why does it have a vacuum b7kzhq ev 7e2st b0(uy6etween its two walls?

Imagine you have a wall that is vefxo +ddkf/x /b54u9w n4wy6tury well insulated — it has a very high thermal reskonf txy49d wudx/4b+/u5 6f wistance, $R_1$ 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 throughh.wg k u2 ),,fqkhtmzl7*imm+ windows by the following processes: (1) ventilation around edges; (2) through the frame, particularly if it is metal; (3) through the glass panes; and (4) radiation. (a) For tw ,k zt) i,lum+27hqm*mkghf.he 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 m:j rx0 c2wk2nr r7rei8ore heat than a piece of shiny metal. Yet the wood7 8n2wr0rrxjik r:c e2 feels less hot than the metal when you pick it up. Explain.

The Earth cools off at night much more quickly when the weather is clear than hb)foq6 r.fufr:u2p) lj.(evwhen cloudy. Whe2r rqh p:u)jo(. u)b. 6ffflvy?

An “emergency blanket” is w0w xq(7sk*stsbst2ux+ yc9 5 a thin shiny (metal coated) plastic foil. Explain how i7 0 sxtqkbswc5sux*9( +2wyts t can help to keep an immobile person warm.

Explain why cities situated by the ocean dog;6 qg* ) prw;vqtrwn8xg 7+tend to have less extreme temperatures than inland citi )rnr 8qw ;gwgpdgt+*vqxo 6;7es at the same latitude.

  How much heat (in joules) is requv*v8 ucba3vg(fv( uk6 ired to raise the temperature of 30.0 kg of wateu g8 3vf*vvku(c(v b6ar from 15 $^{\circ} C$ to 95 $^{\circ} C$ ?    $ \times10^{7 }\,J$

  To what temperature will 7700 J of heat raise 3.0 7ek* ok)m cw g:jsq502n /yaq,n8xornkg of water that is initially nwqca0)rej, gqxoy s k5 o:728*nk/nmat 10.0 $^{\circ} C$ ?    $^{\circ} C$

  An average active person consumes about 2500 Cal 2op2rlau1bfc 2e 1xgbbt :: fmf .n87ca 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 (Btuz8jwv57o s 5fu) is a unit of heat in the British system of units. One Btu is defined as the heat needed to raisow7 j5fz5s8vu e 1 lb of water by 1 F $^{\circ} $ . Show that
1Btu = 0.252kcal=1055J

  A water heater can generate zuxkaeq3h-tq7. 1s*l $32,000\,kJ/h$ 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.bw7er, dn-pk;8c le u* Estimate how long it will take to heat a cup of soup (assumbcwereu- * 78;lp nkd,e this is 250 mL of water) from 20$^{\circ} C$ to 60$^{\circ} C$ .    min

  How many kilocalories are generated when the brakes are u/f.f: o,sg jr *hitx:nsed to bring a 1200-kg car to rest frr*tg:/j, . :nffsh ixoom a speed of $95\,km/h$ ?    kcal

  An automobile cooling system holds 16 L of wakbvqfl)k .np y 22-lt(ter. How much heat does it absorb ib.p)vt2 kl(fnlyk-q2f its temperature rises from 20$^{\circ}C $ to 90$^{\circ} C$?    $ \times10^{ 6}\,J$

  What is the specific heat of a asi6xsd6b;r5 -ul47phi- vef metal substance if 135 kJ of heat is needed to raise 5.1 siiexb ;pd6vl-ash654f ur7 -kg of the metal from 18.0$^{\circ}C $ to 31.5$^{\circ} C$ ?    $J/kg\cdot\,C^{\circ} $

  Samples of copper, aluminum, nopfa6;c vunai6 j */rper5s 5 +qtq ;bp0s35cand water experience the same temperature rise when they absorb the same amount of heat. What is th5b3;5 af/q;jniuc+n pre6pv o0tp qs sc5ar6* e ratio of their masses? [Hint: See Table 14–1.]$m_{Cu}$ : $m_{Al}$ : $m_{H_2O}$ =    :    :   

  A 35-g glass thermometer reads e iepv3q//os8ai7rm* 21.6$^{\circ} C$ before it is placed in 135 mL of water. When the water and thermometer come to equilibrium, the thermometer reads 39.2$^{\circ} C$ . What was the original temperature of the water?$T_{iH_2O}$ =    $^{\circ}C $

  What will be the equilibrium temperature when a 245-g block of copper at 2;n q g*caierp g;(v9 .qwe(*hp85$^{\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 xx*j7u k y8qa.(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 x gzw za9 qqnbgkl-7u+)b 6k0: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 comyzjo 9(7y r *z*v bq;)tvgtj-ffeepot to bring to a boil 0.75 L of water initiallvyt7)gbozzjtv y;j*m*( -qr9 y 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 contx l 0g5jgk-/gpent of 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. The aluminum bomb has a mass of 0.725 kg and is placed in 2.00 kg of water contained in an aluminum calorimetp x/gj0gkg-5l er 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 7g*mzeuafg7 : lv1f: piron 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 hame8vz:n(jhz8ewrld/o7)g j*ec6 h 1yg mer 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 objekjo+2whi-j g 9ct is defined as the amount of heat needed to raise its tempeji2 + okwjg9-hrature 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 l 5 lr54ay-v:jv iog: krt4zkl0u/ vwxfg:2v0 melt 16.50 kg of silver that is initially at 20$^{\circ} C$?    $ \times10^{6 }\,J$

  A 0.095-kg aluminium sphere is dropped from the roof of a 4/ 53ibkk kwyyf3q (vb*a1w1sf5-m-high building. If 65% of the thermal energy produced when it hits the ground is absorbed by the sphere, what is its temp5wbf1byfaykwqi313 ( s /k*kverature increase?    $C^{\circ}$

  During exercise, a person may :bikcb5) cf5 qlzkb:-a;ga6n give off 180 kcal of heat in 30 min by evaporation of water from the skin. How mc:-)in bkb gbqzf6c:;kl a a55uch 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 intri y632ojzn7 zo an insulated container of liquid nitrogen. How much nitrogen evaporates if it is at its boiling point of 77 K and has a latent heat of vaporization of7ji23zzrn6y o $200\,kJ/kg$ 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 fr dbd;2jp6 -wjiom 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 kgnxj2i7:)pui dh2d.2df i:t vb 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 bic a(j 2rct4hnj x h5oj:r4e2sinw+z/6uxnpu01yclist consumes 8.0 L of water over the span of four hours. Making the approximation that all of the cyclisjnux4ejst1or6a5: w22r+hxp4 i0c nzn/ (ujht’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 10f3l,wk k4r1ll, ufk1k0$^{\circ} C$ 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 hp*69/ozie 4qb( )yv9ovsq sq 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 travelizwy q y:,wgs;.tb.++j,hkohlng at $250\,m/s$ penetrates a block of ice at 0$^{\circ} C$ and comes to rest within the ice. Assuming that the temperature of the bullet doesn’t change appreciably, how much ice is melted as a result of the collision?   g

  A 54.0-kg ice-skater moving at jydp4gtxt8s4 hz4) 3q $6.4\,m/s$ 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 nh2pw0;:daxx( s(gg -ozhd v4that the 8.2-g lead bullet that was stopped in a doorframe apparently melted completely on impact. Assuming the bullet was fired at room temg4hdgs 0( aox ;wp:2zx-vh(dnperature (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 c4 aup-+y43x ljigxa)ej5mt x3 m 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, assuminlt6 j(w- tq uw8yk way0,xrw;/g that there are strong gusty winds and the external te0ju r;tqaww6t8 ww-ly,x(y k/ mperature is -5$^{\circ} C$   $ \times10^{4 }$ W

  (a) How much power is radc82 tjp, dpa9biated 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 flows by conduction from dk:vnj1lkqy+1wv6z9gt sh 9( r0zws +the blood capillaries beneath the skin to ys( dzk09z1hwv 6l 9nqkj :1gs+vrw+tthe body’s surface area of $1.5\,m^2$ If the temperature difference is 0.50 $C^{\circ} $ , estimate the average distance of capillaries below the skin surface.    $ \times10^{-4 }$ m

  Two rooms, each a cube 4.0 m per side, shw,o ate-beo1(*a cz2(xoda0u are a 12-cm-thick brick wall. Because of a number of 100-W lightbulbs in one room, the air is a(zc*xao-a odu wa e(t12,ebo0t 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 fq0:u5bm ,ygua 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 as;jy s: qri/fs24o j+lnd cross-sectional area are attached end to end (Fig. 14–18). The copper end is placed in a furnace maints:;r f s42ij /oj+qylsained 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 Eart)cvc 8d.yqsvepta+c7 /8jdp8o, *nv 1e)avfvh receives enedvp .fdj8 acny8qcs81)/vt+ oea v7,vepc*v)rgy 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 throug;gyezxwt7 ( e-n2wz 6eh a glass bulb that has a radius of 3.0 cm and is 1.0 mm thick. What is thetz7e;w2n -z 6yg(wexe difference in temperature between the inner and outer surfaces of the glass?   $^{\circ}C $

  Suppose the insulating quay91vkkktd;+-fbhpka * gl 8 c9lities 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 total rate pb *d9afk1g- tyvlk89+;ckkh of heat loss through such a wall, if its total area is $240ft^2$ and the temperature difference across it is 12 $F^{\circ} $?    Btu/h

A double-glazed window has two panes sz,le. .qnkw*ic3zj1 of glass separated by an air space, Fig. 14–20. (a) Shojqcziz. kw1 s.n3e,l*w that the rate 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 11.0 kg of ice at 0ei;qlwbi,ax0 cu- 1xvz tgf(5u1t;z 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. ftu7z:r .j4 zon-tyvc 3r.-f*bnrz0m20 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 thermalsmn,p;q g,z m s5x1qk. energy is contained in the world’s oceans, estimate the heat liberat ss5;. n1zxpkmqg,mq, ed 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 estimate.)    $ \times10^{ 15}\,J$

  A 15-g lead bullet is tested by firing it into a fixed block of wo5u,h06 ozhwi)f ;fwza 8e0iqwod with a mass of 1.05 kg. The block and imbedded bullet together absorb all the heat generated. After thermal equilibrium has been reached, the system has a temperature rise measured asw hwfuiqhz5z)i0 6owfa,;08e 0.020 $C^{\circ} $. Estimate the entering speed of the bullet.    m/s

  (a) Find the total power radiated into space by therm5, 6xzihf d1xm o)s6v3d9rv Sun, assuming it to be a perfecth5ms61 6d ifv v,rdr zx9o)3mx 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 :brqk7h*z dd270-kg person may generate $200kcal/h$ Assuming that 20% of this goes into useful work and the other 80% is converted to heat, calculate the temperature rise of the body after 1.00 h if none of this heat were transferred to the environment.    $C^{\circ} $

  A 340-kg marble boulder rollmh j)dvs:a/,vs off the top of a cliff and falls a vertical height of 140 m before striking the ground. Estimate the temperatuvvhja,m: d)/sre rise of 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-L inxt7;2v h ob7cksulated pail of water initially at 20 b7vh ct72ok;x.0$^{\circ} C$. If the final temperature of the water–lead combination is 28.0$^{\circ} C$, what was the initial temperature of the lead ball?    $^{\circ}C $

  A mountain climber wears a goose down jacket 3.5 cmx,vs ;;ovrw3q(5oqxo yx8jm 1 thick with total surface are w oq,jo v(5;xmx1x8q3yrvs; oa $1.2\,m^2$ 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 raoim:dgu d/0 xjp vq*+k*(jg .gfa/p aa10)mkxte 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 sx/p- yx b-rbb03ry-e be conducted from the interior of the body to the surface. Assume that the thickness of tissue is 4.0 cm, that the ski-rbe-3x yby b px-/0rsn 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 thickllkz0)pkw46v0z +i x j (assume conductivity of air) and arkz jzkv0 0x+p il6w)l4ea $410\,m^2$ 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 6x-vh2gtror: q..dj .(gyymi 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)cprxeyt83 r65 in Problem 58, take into account radiation from the leaf to calculate how much water must be transpired (evaporated) by the leaf per hour to maintain a rp3rc te 5yx68temperature of 35$^{\circ} C$.    g/h

  An iron meteorite melts when it enters the Earth’s atmosphere. p kmm7- en9/oc70wpv bIf its initial temperature was e o97mkpbn/w-pm07v c-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 i:dk1 0w6nx5glaf9nu6to o49w /q cld vncreases 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 hit a s2y0e7txawt)oa: ; w r i(dfyv+oft rubber ball at a wall until they are about to drop due to dehydration and exhaustion. Assume that the ball hits the wall at+v:)yxtit0edaw27wy fa ( ro; 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 resulub8*vsb( pox.t 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 by conduction and rax 7 *32rghtowudiation at a rate of about 200 W. Estimate how long it woul3o wrhg *xtu72d 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 dis8 4ykvqs 0o5 o1y6dgyvv:: amohwashing, there is “no hot water” left in the 50-gal (185-L) water heater. This suggests that the tank has emptied and refilledaq:ky y0oo68 v 1y5 movdv:4sg 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 60m760+y0t ws/ tt2g6pk thgmb u-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.    $^{\circ} C$