What happens to the work done6;fe j qq;+muci(u4ch when a jar of orange juice is vigorously shaken?

When a hot object warms a cwygsl:nu1 y7 0iit3 0m 3beia6ooler object, does temperature flow between them? Are the temperature changes of the twole wb13yanti7m 30: 0iiuysg6 objects equal?

(a) If two objects of different temperatu; w6xu24ni8g;ffigr i res 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 4ii2urfw;x 8gi6f ;gnthe internal energies of the two objects are the same? Explain.

In warm regions where tropical plants grow but the temperature may droult,.govu9kb gm98 tb,5qqr. p below freezing a few times in the winter, the destruction of sensitive plants due to freeziv r8m,u59oq qkt gul,.9bg.tb ng can be reduced by watering them in the evening. Explain.

The specific heat of water is quite large. Explain why this fact makes w4n rzo dwk8aait/o*4 5ater particularly good for heating systems (thainrto k44d ozw8a*/5a t is, hot-water radiators).

Why does water in a metal cant9( 8mue dvc7q794 ncnv*7 x sujkuzto;een stay cooler if the cloth jacket surrounding the canteen i 7uto9vm u*cq94e;xud s 7(nvk7cznj8s kept moist?

Explain why burns caused by steam on the skin aelg)+d(ms: *xkd6epire often more severe than burns cause k l:m pieg(+dd6esx)*d by water at 100 $^{\circ} C$ .

Explain why water cools (its temperature drops) when it evaporatk j*a19 k9qsuu,o1b +kq,;npt e+de vaes, using the concepts of latent heat and internal energy.bo+v*qs,qkeka+ujatpd 1,1ku 9;9e n

Will potatoes cook faster if thxh/n ,gru.nqo: w *y f)uh tkf(x(),qfe water is boiling faster?

Does an ordinary electric fan cool the air? Why or why not? If not, w -b*ioxn gqay -)zh*-ihy use it?

Very high in the Earth’s atmospherebn n9i6r7mjw8 , 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 d,c y6p)2vb ktcovering themselves with sb6,pc2 ) ydtvknow. Why would they do that?

Why is wet sand at the beach cooler tt-w qk aly 0+xcy8:;qto walk on than dry sand?

If you hear that an objecc ou6 uch6vam89m3jk)t has “high heat content,” does that mean that its temperature is high? Explai89ch 6 m)6aj3uvocukm n.

When hot-air furnaces are used to heat a house, why is it important that there 09ic v5 g yjwddhp3egz2 i )gnccc) 4n9w+90ypbdz9 vpg5 y94in cnd wy2ch3 90)gwjec0p +cig)e a vent for air to return to the furnace? What happens if this vent is blocked by a bookcase?

Ceiling fans are sometimes reversible, so that they driv tak ux 9n9av()aobc40e the air down in one season and pull it up in another season. Which way should oc 09xt9a)n4abauvk (you set the fan for summer? For winter?

Down sleeping bags and parkas are often specified ;3xw.r:sz e:oi*jqju-8qy ti as so many inches or centimeters of loft, the actual thickne.u jsz :tjyx;i8o3q: w eri-q*ss of the garment when it is fluffed up. Explain.

Microprocessor chips have a “heat afvgh .z-c29a sink” glued on top that looks like a series of fins. Why is it sha9g-c 2hazav f.ped like that?

Sea breezes are often encountered on sunny days at the tvz,ua ; s4 ; c(zhc(2 lw7iojyk5y rxu+h8g2gshore of a large body of water. Explain in light of tgyu7l ahur (4, k+xczjv y;5(s zwi 2g2;hct8ohe fact that the temperature of the land rises more rapidly than that of the nearby water.

The floor of a house on a foundation under which the af- p.1jqnvj,gl9u 3s xir can flow is often cooler than a floor that rests directly on the ground (such as a concrete v 9guqjl.- f 3jxs,pn1slab foundation). Explain.

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

Explain why air temperatur8 fzbfd gu24w1p;pz*y6 kje.we readings are always taken with the thermometer in the pf1zu4* f;w8dgebp j2 6w y.kzshade.

A premature baby in an incubator can be dangerously cooled even wg 9 no:zcw. 19fqxcl-*o4mujchen the air temjz mo-4 .1cocxflguwn :99c q*perature in the incubator is warm. Explain.

Why is the liner of a thermos bottle silvered (Fig. 14–15), and why does if+y3 bs2th,dgu(e 3evt have a vacuum between its(3h yv ugs,edte+2bf 3 two walls?

Imagine you have a wall that is rti0q.vm *mm65f)vo -omnbt8 very well insulated — it has a very high thermal resistanrobvtim-no8 *5.0m tqfmv )6mce, $R_1$ 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 windz,vjkozxac+ s) 1+l5 oows by the following processes: (1) ventilation around edges; (2) through the frame, pavcxl j+5s +)ao,1ozzkrticularly if it is metal; (3) through the glass panes; and (4) radiation. (a) For the first three, what is (are) the mechanism(s): conduction, convection, or radiation? (b) Heavy curtains reduce which of these heat losses? Explain in detail.

A piece of wood lying in the Sun absorbs more heatddok vh/cyu -+5uk 6a6 than a piece of shiny metal. Yet the wood feels less hot than the metacvduo y65+/uk-h6 ka dl when you pick it up. Explain.

The Earth cools off at night much more quickib)ygu62lqu;vf 0)eq jm0g: y wz3q +kf+/vgvly when the weather is clear than when cloudy. Why?m+ ezy/w;) vk :)gif+lgq vb q2vfj0y6 gu3q0u

An “emergency blanket” is a thin shiny (meta7 jqhis.; ud3j20w khvj *yj: gzag..il coated) plastic foil. Explain how it can help to keep an immobile person warm.jiw.; j 73 vjyu*a0:ids2gg.qz.hjkh

Explain why cities situated by the ocean tend to have less extreme tempv tcb51vp i*y.eratures than inland cities at the yi *t.v pbc15vsame latitude.

  How much heat (in joules) is requ(aua 5 mf+tz4o0k 6qb*n9x meoired to raise the temperature of 30.0 kg of water f+o 6x z4qa0et( 9ufakmomnb*5 rom 15 $^{\circ} C$ to 95 $^{\circ} C$ ?    $ \times10^{7 }\,J$

  To what temperature will 7700 J of heat raise 3.,1 gjmycxmpmoqq ,b7;97zbl)0 kg of water that is initially at 10.0qg;,1m7ml ocj )bb,9yzqmp x7 $^{\circ} C$ ?    $^{\circ} C$

  An average active person consumes abou)wb y7g 6viik0k h;5ayt 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 British syst8rwuu*r76wvv jz/ *r .;sh omxem of units. One Btu is defined as the heat needed to raise */o j;u6rzwwu s 7xvr8rm.v h*1 lb of water by 1 F $^{\circ} $ . Show that
1Btu = 0.252kcal=1055J

  A water heater can gener( xvx6ho ncp pw;h3h;9blm29late $32,000\,kJ/h$ How much water can it heat from 15 $^{\circ} C$ to 50 $^{\circ} C$ per hour?    kg/h

  A small immersion heater;xb dw7yzve2 ) is rated at 350 W. Estimate how long it will take to heat a cup of soup (assume this is 250 mL of water) wzby)7ve2 d; xfrom 20$^{\circ} C$ to 60$^{\circ} C$ .    min

  How many kilocalories are generated when the brakes are used to brin klmph9;4i,8gx+ wk mjg a 1200-kg car to rest fghk8j;m x9im4l+ kw p,rom a speed of $95\,km/h$ ?    kcal

  An automobile cooling system holds 16 L of water+lz4rpuhm 9 .li/i1 gg. How much heat does it absorb il.g4 izh/+mp ig19 urlf its 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 heatf,.8xb wg w.yw is needed to raise 5.1 kg of the metal from .fbwwxygw8 ., 18.0$^{\circ}C $ to 31.5$^{\circ} C$ ?    $J/kg\cdot\,C^{\circ} $

  Samples of copper, aluminum, a762eyapzgf6r yl2nb0(5id*:/ qg vir ckw )wfnd water experience the same temperature rise when they abwdy(5 q760gec2f2awr il pzy) g i6v/*br:knfsorb 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 reads 21.u qlq* 9hqb9:k6$^{\circ} C$ 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 block0bdpfb- g6:st 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 (t3 u *wz)zc3bedl iy3o/ ;b7bfmass = $0.4\,kg$) 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 to 33s 4niefl8*/ is0$^{\circ} C$ 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 k)8ts te 0w 6txpg+l0e0.75 L of water initially+stxe0w 6p tk8get0 )l 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 bp9*9v u+v,g xyzdws,a x6l*n 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.s 6,uw9 xxbapgzvv,*l* d+9ny00 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 6xqfu3 )wtxf0 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 hammdh xssz:;. 7tter 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 amouna8afb ze*2/dy3lkil (t of heat needed to raise its el2ka/alb3 y f8d*(zitemperature 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 1sd- f+z 7ixvgc /h:l1w6.50 kg of silver that is initially at 20$^{\circ} C$?    $ \times10^{6 }\,J$

  A 0.095-kg aluminium sphere is dropped from the ro she6 5ilp.nq5cm40nup y /oa tz9ai*+a5zih;of of a 45-m-high building. If 65% of the thermal energy produced when it hits the ground is absorbed by the sphep; .0+tu6q ziay5soea5 lni /z5na h c*4hpi9mre, what is its temperature increase?    $C^{\circ}$

  During exercise, a person may give off 180 kcal of heat in 30 min by evap i5( zbi-9,zyas a0ghforation of water from the skin. How much watezi,s5bgf a9zy-ha(0 i r 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 intdt4*7en:bsp n0w )a m:lt;lolo an insulated container of liquidl*wlo0 en;74d n) ltp: mtsa:b nitrogen. How much nitrogen evaporates if it is at its boiling point of 77 K and has a latent heat of vaporization of $200\,kJ/kg$ Assume for simplicity that the specific heat of ice is a constant and is equal to its value near its melting point.    kg

  A cube of ice is taken from the fx* s5.cunu u h44bl.p)y00ewf ied4wvreezer 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 kg of watee; khfw- ln+fh:-5zse )ij fx/r 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 c7a*useemd4m cn 3z; w9onsumes 8.0 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 duriemw cz9*7sdneu4ma 3 ;ng 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 attbf0+5b dx6tds*ngy 9 100$^{\circ} C$ 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 mercu2:lbkg-wnjx, hs1 (s sry 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 a1rar,tvib ; x 5)miutcwk,/t7t $250\,m/s$ 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 momav:ndo7w5oz)u g 8p))i l aw6ving 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 inve 6bzrcamm(;)qstigator notes that the 8.2-g lead bullet that was stopped in a doorframe apparently melted completely on impact. Assuming the bullet was fired at room tez6;q ()racmbmmperature (20$^{\circ} C$ ), what does the investigator calculate as the minimum muzzle velocity of the gun?    m/s

  One end of a 33-cm-lon spjlkas5y9)s h j;0h1iae*j(g aluminum rod with a diameter 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 of heat flow by conduction/,g3ecter/e ao) k f;8o;:t3v llk hwf in Example 14–10, assuming that there are strong gusty )eeoerh vo,8wla;k :/ ltc;f tg/3f3k winds and the external temperature is -5$^{\circ} C$   $ \times10^{4 }$ W

  (a) How much power is radiated b: db(89+emamlwnen; f )3s q1b9kk lg7dvomm+y 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 +v u0q-,uhr.- oerorjconduction from the blood capillaries beneath the skin to the br rve- horu j,.+-oqu0ody’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 4xj o;gu/d. n4nh,7f7f ug y9ob.0 m per side, share a 12-cm-thick brick wall. Because of a number of 100-W lightbulbs in one room, thexfbno/,yo;9u 4jd uf g7g7.nh 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 3jugt )bt5bw(fbb4)fof 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 cross-sectionalom7tuoia ew+01wwh05;aym ( t area are attached end to end (Fig. 14–18). The copper0 hwtuymwa7iwo 5oe;m a+1(0t 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)mw1) z49bhr0uh htzf which the whole Earth receives energy from the Sb)wzmt1uzh94h0 rhf )un.    $ \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/baa )1 p*mug bs; /pxxjxk)t,d through a glass bulb that has a radius of 3.0 cm and is 1.0 mm thick. What is the difference in t)bgkxs;, a p j) u/*mtxp1x/baemperature between the inner and outer surfaces of the glass?   $^{\circ}C $

  Suppose the insulating qualities of the wall zja0x,m /bzg;pwse17p4-pa v of a house come mainly from a 4.0-in. layer of brick and an R-19 layer of insulatio 1vj ;p ag-ppxwabem 47,0/szzn, as shown in Fig. 14–19. 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 window has two panes of gl 8kyz ec0uomi-,,qq8 pck.a:fass separated by an air space, Fig. 14–20. (a) Show that the rate of he8k8- q ,0: iy.ocmapuqekf,cz at 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 ax ja/c +da2*9n;/vbc tpsneoa q: v--bt 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 0.20cs jx(7 umi rov9vh-du,ids5y x551 2e 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 6d1 -3d:wyy k;5zszf df9wsmvthermal 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. (Approximate the ocean water 3w 19fy-d s: w6kdmzy5v;szfdas pure water for this estimate.)    $ \times10^{ 15}\,J$

  A 15-g lead bullet is tested by njhcftl q+v:928uu* k firing it into a fixed block of wood with a mass of 1.05 kg. The block and imbedded bullet tog*c89n:h2ufu ljvqt k+ ether 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 po)u3ca-d h atrbmwlt ip -34x53wer radiated into space by the Sun, assuming it to be a perfect emitb a5l34i c auhdtm-3-w rt3px)ter at $T\,=\,5500K$ The Sun’s radius is $7.0 \times10^{ 8}\,m$    $ \times10^{ 26}\,W$
(b) From this, determine the power per unit area arriving at the Earth, $1.5 \times10^{ 11}\,m$ away (Fig. 14–21).    $ \times10^{ 3}\,W/m^2$

  During light activity, a 70-kg person may gda** it:vfnx*enerate $200kcal/h$ 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 3kw vbtxu)f3-oyr70 drolls off the top of a cliff and falls a vertical height of 140 m before striking the ground. Estimate thbd)f tkv-37oyr3uxw 0e temperature rise of the rock if 50% of the heat generated remains in the rock.    $C^{\circ} $

  A 2.3-kg lead ball is dropped into a 2.5-L insulated erforj +ec,*mxs5 * sf*, 5h9kyyu rcu8h,f/apail of water initially at y8r5uey fohe* s,jh 9 cr,af+kuc,xms**r5 f/20.0$^{\circ} C$. 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 cm thick with totald;y mnr8b3v0t tn*1 yn surface area;8tnmvy01n3nryt *d b $1.2\,m^2$ 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 averbm3,.p-)z5cpyvoi2, mwd0n p yk q,udage metabolism rate of about $950\,kcal/h$ during a race. If the runner has a mass of 55 kg, estimate how much water she would lose to evaporation from the skin for a race that lasts 2.5 h.    kg

  Estimate the rate at which heat can be conducted from the interior +d ) 5 (3qjwtr8xnexs*tzds8oof the body to the surface. Assume that the thickness of tissue is 4.0 cm, d3 *swdz)(8on5xqtjs tx +8e rthat 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 cond 0 wmg7 lzj.e4 fei9i,epqf3(xjp(s)z uctivity of air) and areamex9fsifw.e( q,pje73 pil)4jgz( 0z $410\,m^2$ 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 ar bwk. 8dafthj 9uyd0/g9a* 4lt $220\,m/s$ 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 fz;xt t+ / s zo*xy9ftye+-nitnn;5wc 15 vkea.rom the leaf to calculate how much water must be transpired (evaporated) by the leaf per hour to maintain a temperature/;zit + ; ay1f*znxe+tnywtkx-5ec s .tnov95 of 35$^{\circ} C$.    g/h

  An iron meteorite melts when it enters the Earth’s atmosphere. I+oqaqn v;ooqccf() 9 -aq) sx8f its initial temperatxfa(c)co- 8+no qvq;9 )saoqqure 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 in)v4ct.m q/,j t9tuesicreases 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 soft rubber ball at a jk i6au, (xpv.q*ex/a wall until they are about to drop due to dehydration and exhaustion. Assume that the ball hitx.a(,*ku/6vjp ieq a xs the wall at a velocity of $22\,m/s$ and bounces back with a velocity of $12\,m/s$ and that the kinetic energy lost in the process heats the ball. What will be the temperature increase of the ball after one bounce? (The specific heat of rubber is about $1200\,J/kg\,$$\cdot\,C$)    $C^{\circ} $

What will be the final result when equal mybfwp.82pv*/odd7 1:w ke sahasses 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 conducti wg/,e 1oetg0kon and radiation at a rate of about 200 W. Estimate how long it would take for th1 ewgok,g/t0ee 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 “ ,dvf;yi .8el9cf)/bnb4wzpuno hot water” left in the 50-gal (185-L) water heater. This suggests that the tank has emptied and refilled .pzcu b48)wf, /9e;yfn dlb viwith 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 lightbulw8w1v6 bu9s8t va9/3a rma esmtwo/ p5b 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.    $^{\circ} C$