What happens to the work done when a jar of orange juice is tshy,o u*c9 5dyrf 09k3emsc1 2erhx;vigorously shaken?

When a hot object warms a cooler object, does tp45s:kxch6q bemperature flow between them? Are the temperature changes of the two objects ekxs c5 6p4:bqhqual?

(a) If two objects of diffe)pldu :hu(.jd rent 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 the two objects are the same? Explai: . uuj(p)ddlhn.

In warm regions where tropical plants grow but the temperv5 i9 s./ gfqla+*vl4bokff)uature may drop below freezing a f)lvas foiq+k95gu lf/ b4v*. few times in the winter, 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 largrsd f-j* 3fp9we. Explain why this fact makes water particularly good for heating systems (that is, hot-water rad j*-r 3fwf9psdiators).

Why does water in a metal canteen stay cooler if the clotk4)15qn6f8 prkhf:g amm/ poth jacket surrounding the canteen is kkn54pamp fh1t:q/6mkof r) 8gept moist?

Explain why burns caused by steam on the skin are 2cvkn(aq- jxv5k0.c tbyy0 . c7cv 6fyoften more severe than burns caused by water .cy c.-(cqnvfa6 bykkvyvx2 0j5tc07at 100 $^{\circ} C$ .

Explain why water cools (its temperature drops) whe0b:ct t- jm7l2ay ky8)z2xzuyn it evaporates, using the concepts of latent heat and iz-k j)8lt x2cumtbz:0ayy 2y7 nternal energy.

Will potatoes cook fasterp x xosf4gi /6*pjg7p fg.23erhi/uy6 if the water is boiling faster?

Does an ordinary electric fan cool ai-1t(v- jtbr the air? Why or why not? If not, why use it?

Very high in the Earthkfy dt+:syx - (txxo+16vcl+r’s atmosphere, 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 bf0tq0 2 c)znhby covering themselves with snow. Why would they do hcfn0 q t)zb02that?

Why is wet sand at the beach cooler to walk on2z ;hp z7bo+hi than dry sand?

If you hear that an object hqu8eb) 1dmey 3as “high heat content,” does that mean that its temperatu31b ee8)yqdumre is high? Explain.

When hot-air furnaces are used to heat a house, why is it important that there t1 lek58 r3c 3e6qehjlbe a vent for air to return to the furnace? What happenree 13eh8qk 5ct36ljls if this vent is blocked by a bookcase?

Ceiling fans are sometimes reversible, so that they drif tpl .( 8janxyw8-0dive the air down in one season and pull it up in another season. Which way should you set the fan8f y.ipnt(x-ja0l 8wd for summer? For winter?

Down sleeping bags and parkas are often specified azj 2;kr-fsww r nurd:d(295kx s so many inches or centimeters of loft, the actual thickness of the garment whenkrd2kf 2nx(udww s:9r;- 5rjz it is fluffed up. Explain.

Microprocessor chips have a “heat sink” glued on teybv-9*ov w6gm3gy/lf n+ qx;op that looks like a series of fine6 ;- g+9l fqywxvy3 o*vmg/nbs. Why is it shaped like that?

Sea breezes are often encountered on sunny days at thz j7+l;fs/ait e 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 thtfi 7j/z +ls;ae nearby water.

The floor of a house6g)omuq o t.f( on 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 foundation). Expl. omgqf( ut)6oain.

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

Explain why air temperature readings are alwaeb;cm 6 r;;r oda9dxw0ys taken with the thermometer in the sha0 ;a9rb;cex ;mrdo6 dwde.

A premature baby in an incubator can bey ow.7o/yc ilfp l9ufyv73x7 * dangerously cooled even when the air temperatur7o397ll / pywvi*.xo7cyfyu fe in the incubator is warm. Explain.

Why is the liner of a thermos bottle silvered (F-l ti- 2wg;k; zn:sfifig. 14–15), and why does it have a vas; ikg:-f- wl tifzn2;cuum between its two walls?

Imagine you have a wall that is very well insulated — it has a very higzvuw p66 2mrz72 p,gpktq 9nv6h thermal resistanceupmw7r2 q,629ptvpzv kg66nz, $R_1$ 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) ventilationgg6d v 8)yp,( tsedfzc3 (x)in 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 these heat losses? Expl8ei,g y3 ztpgn(dv) c6)x(f sdain in detail.

A piece of wood lying in the Sun absorbs more heat than a piece of shiny metay*wkdw oop*:d a1q)r6 q*8ien 2d 3ooel. Yet the wood feels less hot than the metal when you pk *)e3:d1p qqdo6da*2 ne*o woy8iworick it up. Explain.

The Earth cools off at night much more quickly when the weather is4ylkn :k x+4dk clear than when clxk n4lkk +:d4youdy. Why?

An “emergency blanket” is a thin shiny (metal coated) plastic fou vcf 9a;ukd -; i65d9oqxqa;eil. Explain how it can help to keep an immobilek xq;9fdavca qu d-5ui;e ;o96 person warm.

Explain why cities situated by the ocean tend to hyan: klku /(6q;;enf7zxb8 w-kpsd8x ave less extreme temperatures than inland cities at the same la- (6k w88a; zpxe: /7 nndslxbyq;kukftitude.

  How much heat (in joules) is required to raise + 4gydd8 wtyz8ogh6-c the temperature of 30.0 kg of water froogwz c-d4+ ht8y8d6gym 15 $^{\circ} C$ to 95 $^{\circ} C$ ?    $ \times10^{7 }\,J$

  To what temperature will 7700 J of hea9q5,h3fd1iz zd.n5 wad 5 jufnt raise 3.0 kg of water that is initially at 1adzw3dq. nz5hj5i udffn,951 0.0 $^{\circ} C$ ?    $^{\circ} C$

  An average active person consumes about 2500 Cay 9 mf4w4tfze r1-3fctl 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 British system of units. Oa 7-2nx3c6jek xs3rkjne Btuj xce7rjn-3xa2ks3k 6 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 gfm sh/s7vh,d fm44rw(nkc.o ,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 ratew-hi: ;xzd3u tz*vd4fa 2,yljw 1n or2d at 350 W. Estimate how long it will take to heat a cup of soup (assume this is 250 mL of-,zu ydd3zj ; i wlta2r :vnox41*wf2h water) from 20$^{\circ} C$ to 60$^{\circ} C$ .    min

  How many kilocalories are generated when the brakes are m)wu y 9jk5umw(*ddv)cf-/lj 4tmy :j used to bring a 1200-kg /v*u yf5 cyu)jj :jt )ww(d4md-m9mlkcar to rest from a speed of $95\,km/h$ ?    kcal

  An automobile cooling system holds 16 L of water. How much heat xhd j 9-irfz)fn-* d d7i.5wasdoes it absorb if ixi*sh f7d .)rw-a-59z ddij nfts temperature rises from 20$^{\circ}C $ to 90$^{\circ} C$?    $ \times10^{ 6}\,J$

  What is the specific heat of a metal substance if 135 kJ of heat is needed u hh f0j ji1c80uqa*/0qbs1 xtto raise 5.1 kg of h 1q1xut/j sh *0ifcabj80qu0the metal from 18.0$^{\circ}C $ to 31.5$^{\circ} C$ ?    $J/kg\cdot\,C^{\circ} $

  Samples of copper, alui tpj a(yfa0 k35sg4tu.-b a5gxp4j7 bminum, and water experience the same temperature rise when they absorb the same amount of heat. What is the ratio of their masj4k7jbxu.tiaf( patg5y g4bp03 -a 5sses? [Hint: See Table 14–1.]$m_{Cu}$ : $m_{Al}$ : $m_{H_2O}$ =    :    :   

  A 35-g glass thermometeaun52kk65 rkxr 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 temperature when a 245-g bl)jm(ibar: -zzock 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 horseshoe23jd n-qssgtcx/yw; ( (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 k-m-pa6 7*vpfuz nx7 fto 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 toin4)uwl mh5) p a boil 0.75 L of water initially at 8.4 nmp5iwlh)u )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 meas 56zxi (*f1 njo*e q41juqqfqnurements. A *j*i6nfufo1nx q(1q45j zeqq15-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 15.0$^{\circ}C $ , and its temperature after ignition is 53.5$^{\circ} C$ .    Cal

  When a 290-g piece of iron at 180hwf c a/nd3z z/1ao(e0$^{\circ} C$ 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 hy p3r6 0uoat;9m7qxshas 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, ofk tz s;p d0u(8(iwj(be an object is defined as the amount of heat needed to raise i;j(usti(dpk e8w 0zb( ts 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 neefuo 2lp2n85j0d gdo w9ded to melt 16.50 kg of silver that is initially at 20$^{\circ} C$?    $ \times10^{6 }\,J$

  A 0.095-kg aluminium s f2te e +jf+w8pd;nc(- ita7dpphere is dropped from the roof of a 45-m-high building. If 65% of the thermal energy produced when it hits the ground is absorbedpepftd(7 t- w+jf;e8an id +2c by the sphere, what is its temperature increase?    $C^{\circ}$

  During exercise, a pe.kp5ijdsx6 3;pvdg f tt; 5ru(rson may give off 180 kcal of heat in 30 min by evaporation of water from the skin. How rs;(tj; ptdu.655x kvg f3pdi 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 poib) qs.aa .u6)6s0jr yvqblcxb(cqp9 - nt is dropped into an insulated container of liquid nitrogen. How much nitrogen evaporates if i 0a )cyxs pqu.cb)6.sqja bl-69br vq(t is at its boiling point of 77 K and has a latent heat of vaporization of $200\,kJ/kg$ Assume for simplicity that the specific heat of ice is a constant and is equal to its value near its melting point.    kg

  A cube of ice is taken from the flyx4u(k)p8khks+ o :ml t3y- zreezer 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 containsqdx y,o,pdw o1 1,b fx::/oytz 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 wlm+( jn:v 24i:zm zco+xl5hz8.0 L of water over the span of four hours. Making the approximation that all of the cyclist’s energy goes into evaporating this water as sweat, how much energy in kcal did the rider use during the ri++2jlcowxm i :lzvh5: zz4nm(de? (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 afjb5z vyl 4/n*t 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 mercw0u2*ruxd d )xury 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 travelkisnui,:r* h*a9 tk6 tx2w6ojing 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 m2xp9 k04obopp -k;rtxch8y. z2.tj heoving 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 d5, / yhyfv;v-vndnm u+.uuv dm;ex00investigator notes that the 8.2-g lead bullet that was stopped in a doorframe apparently melted completely on impact. Assum;.5ymvdfvh+ym x dvn00vu,n-/ ;uueding 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 oc/drw:f;,b1i2rq c;va cj 4sf f 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 conduct,jsrm;a f- ly2ion in Example 14–10, assuming that there are strong gust jya;lms-,fr2y winds and the external temperature is -5$^{\circ} C$   $ \times10^{4 }$ W

  (a) How much power is radiated by a tungsten sp13 v(*5owzrrcx p 9rlhhere (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 g-n dgrwfpmp0 *a9 -+5h 8ejeiconduction from the blood capillaries beneath the skin to the body’s s nep5rgehw-+ -g*80fm9dap jiurface 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, share a 12-cm-thick brick wall. Because hzx(be: y2zj8of a number of 100-W jbh 2z z:y8(exlightbulbs 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 blo/l fu3*rin ;vjck of ice at 0$^{\circ} C$ with a flat horizontal area $1.0\,m^2$ and thickness 1.0 cm? Assume that the Sun’s rays make an angle of 30$^{\circ} $ with the vertical and that the emissivity of ice is 0.050.    h

  A copper rod and an aluminum rod of the same length and crdwaq86 dpj,y b-4;dd06 iuzhl;qd is,oss-sectional area are attached end to end (Fig. 14–18). Td lqdds,dhz,jiwpb;;6i u4 0q-8 6yd ahe 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 aucunb;rt9 ,6 5 sb9ivEarth receives energy from th,b9vtc a;9ur in5sbu6 e 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 dissipate 01vpx(j ecx)yd through a glass bulb that has a radius of 3.0 cm and is 1.0 mm thick. What is the dif1xy(0) vxcj peference in temperature between the inner and outer surfaces of the glass?   $^{\circ}C $

  Suppose the insulating qualities of the wall of a house come mainly hj3(e9g/b5j tfrd g -nfrom 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 is n5/3 d-9jf (bg jethrg$240ft^2$ and the temperature difference across it is 12 $F^{\circ} $?    Btu/h

A double-glazed window has two panes of glass separated by an air spaceyt)h8t09yjgb 9v5 d(en6- zol bu.u bl, Fig. 14–20. (a) Show that the rate of heat flow through (.v5et-bu6j0)lzl8 n bbh9y 9ou ytgdsuch 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 11.04ccp w o)e9i8qfh;e,z 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 wys 8-twu8 6 w/ z8wwhq+szi*kabout 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 world’s och)is/hwv1q 5teans, estimate the heat vq5w/sh) hi 1tliberated 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 ae)c m3m3jge 1block of wood with a mass of 1.05 kg. The block and i33)eamjcmg1 e mbedded bullet together absorb all the heat generated. After thermal equilibrium has been reached, the system has a temperature rise measured as 0.020 $C^{\circ} $. Estimate the entering speed of the bullet.    m/s

  (a) Find the total power radiated into space by the Sun, assub:z7g q.5/pyn)f0quc bo1rls ming it to be a perfect emitt1:nbuplqryc) s .fg /7b5 0oqzer 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 ma* z9t2rh3gte pl1 l* s1nbhnyg;: :xzdy 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 vertical v ylej x+2124hxr:xx)kg kr; gheight of 140 m before striking the ground. Estimate the temperature rise of the rock if 50% of th2r k;xvk4xe2:+gjy 1g lr)xxhe heat generated remains in the rock.    $C^{\circ} $

  A 2.3-kg lead ball is dropped into a 2.5-L insulated vcv9y3wn(tgf ur /0,p pail of water initially at 20.f3rn y/vpwcv ug 90(,t0$^{\circ} C$. 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 c-zu4 i xd8 qr6sz2og9).divijacket 3.5 cm thick with total surface areaoir izizsuvq 6-2c . 48d)d9gx $1.2\,m^2$ 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 ofw7xps7eiwa02yq 5k)e+ noa7i 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 vlu0 gd4,p-y 5iyx ;(65xu3zgdobecsof the body to the surface. Assume that the thickness of tissue is 4.0 cm, tha c60sl;zy y-(vxgx 4oddep5bg5u3u i, t 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 (assume czy85ze*r o +j( yq7lvuonductivity of air) and +zerzojy*l5(v7y8 quarea $410\,m^2$ 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 travelingq2fb) jhe ph1nfe /6l;rl i:)h 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 accoun2 c qaftfp/5hsnqn;) gr1+ 1z vcma8ota8fm/8t radiation from the leaf to calculate how much water must be transpired (e zr58f m+ afto1 vg2 )t8a//chq8qmp;fcsnn1avaporated) 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 atmospd,2/(a- xsa6te klq fdhere. If its initial temperat,tadl-2 (6kx / dqafseure 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 crust increases about 1.0 k; (tj4)gfsk7j w7bdi1 a4vgx 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 rubber bc8 k.; /q* gjdevz6mykall at a walkqgmey6;8 jv z k*/cd.l until they 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 resulth+e9 k ayq3l2q 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 cg*v9x hbtisod,+n 73)b*q4p.c nlg vg onduction and radiation at a rate of about 200 W. Estimate how long its p 3)*b7x+dtlc vq4.*hn,9gognv ibg would 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 6: pnmxr(4gso50-gal (185-L) water heater. This suggests that rn o mg:x(ps46the 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 a 60-W lightuh-2z93 dryeb bulb 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.    $^{\circ} C$