What happens to the work done when a jar of orange juice is vigoroc ;qvhzh1i(u(usly shaken?

When a hot object warms a cooler object, does temperature flow between thuoj13 4o:xg qhem? Are the temper4o ou:gh1qj3xature changes of the two objects equal?

(a) If two objects of diffhxq3tmi b9hfbj*k5ped(n;( / erent 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 objectsb pi;nb(5 kd q*f(h/mx j93teh are the same? Explain.

In warm regions where tropical plants grow but the temperature may drop be3uct3d fvr 8w);m wx(vlow freezing a few times in the winter, the des xvftwv 3ru8);dc3m(w truction of sensitive plants due to freezing can be reduced by watering them in the evening. Explain.

The specific heat of watedv*; /4vta.v 5vxfmuyv7 t)y qr is quite large. Explain why this fact makes water partictv4x. *dy)f vu; ya7/v5mvqvtularly good for heating systems (that is, hot-water radiators).

Why does water in a metal canteen stay cooler if the clotg2 0shwbi ,vmu-7 u iuze)n9s9h jacket surrounding the canteen is kept mou9ghsvw7eu 9i0b, 2ius z)mn-ist?

Explain why burns caused .0xer7nvl m:zt jm xn47r32gfby steam on the skin are often more severe than burns caused by water at 100 tfv mjrr 7l z2x.eg n7340nxm:$^{\circ} C$ .

Explain why water cools (it*)j6hehc w7ch:e wli v(odbw7x)6 9r fs temperature drops) when it evaporates, using the concev* w:wiodh()c9e 7 lxcj)wr 7eb66f hhpts of latent heat and internal energy.

Will potatoes cook faster:*1 q hu4zv3gndbcf*r if the water is boiling faster?

Does an ordinary electric fan cool the air? Why or why not? If not, i3;ixxha87e/dat3 kt. p cexjw(+7e(do +we swhy use it?

Very high in the Earth’s atmosphere, the temperature can b5e2 v*doy /wu-w+k 8x/daiygi q x,)toe 700 $^{\circ} C$ . Yet an animal there would freeze to death rather than roast. Explain.

Explorers on failed Arctic 1.afxvij 1,-wfua.yy expeditions have survived by covering themselves with1fw afu ja v.1y.xyi-, snow. Why would they do that?

Why is wet sand at the beach cooler to walk ogtn ;cs; d+sb6 ye6x6.kc l m8+-ormikn than dry sand?

If you hear that an object has “high heat content,” does that meamks sbpp)9d 1i8txo vo19/is ospcxm*x:k4; ,n that its temperaturo ptxp4/ dsi,obs ;s9pxxi)vkk:sc8 *m9m o 11e is high? Explain.

When hot-air furnacesa/s * kgzww0ie:p4/p s are used to heat a house, why is it important that there be a vent for air to return to the furnace? iz:w0a/s pek /gp w4s*What happens if this vent is blocked by a bookcase?

Ceiling fans are sometimes reversible, so that 7 jznai kfg -;/ ofmph*ad80*uthey drive the air down in one season*anfpfu ;z/* 8go-ajikdh7m 0 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 specifi88e2ff3s. w2 dwi 4guryk:rx7fq chd4ed as so many inches or centimeters of loft, the actual thickness of the garment when it is fluffed up. E8 xguh e3 2rwidwq 4r:ffc4d.y872skfxplain.

Microprocessor chips have a “hc) pvi9 z)h( hoxx1/m:.*mt6ufdwo uzeat sink” glued on top that looks like a series of fins. Why is it shaped like that?6um *mz :d1fhiouv)zhx9 x) .toc(w /p

Sea breezes are often encounte +.paatpgtf+s(h6tk,j2x si6red on sunny days at the shore of a large body of water. Explain in ah +. 6i+(fsk 62pts,agjttxplight of the 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 ai dueus7yse0nr;n (v:7r can flow is often cooler than a floor that rests directly on the ground (such as a concrete slab foundatn e (0v7 r:s;s7eynduuion). 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 take//rx-ie6/khd ,mmr son with the thermometer in the shadd o hm /krr/xm-esi/,6e.

A premature baby in an incubator can be dangerously cooled even when themp ;3;jmjr rh( air temperature in tj h;(jm m;3rprhe incubator is warm. Explain.

Why is the liner of a thermos bottle silveekt p lt)/2 i(0iwh0mrred (Fig. 14–15), and why does it have a vacuu i2(t/m0pwrhlit0e ) km between its two walls?

Imagine you have a wa;a8i.dmzc1 a j(ade 0hll that is very well insulated — it has a very high thermal resistanca (1a a;hd.idmec0zj8e, $R_1$ 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) ventil .v04y*:gosqutf jl m(ation arogv j .(0o:* qlfstymu4und 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? Explain in detail.

A piece of wood lying in the Sun absorbs more heat tha fj ;-( gt1m5ic;qvryom z/6dyn a piece of shiny metal. Yet the wt-yo1q;mi5gvj c( 6/mz; f dryood 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 w:.:b*qezlr4n 5e8ff d m 6lndlhen5 n.*d4:6em 8n rdllqfefzl:b cloudy. Why?

An “emergency blanket” is a thin shiny (metal coated) plastirpg;:v. ;zpqj c foil. Explain how itj;.v ;rzgp:pq can help to keep an immobile person warm.

Explain why cities situated by the ocean tend to have less extreme tempgh52ey3s0 h:ex bi9km ekgk1dra. :(,ztair. eratures than inland cities at the same latit2a0 xh5 yeh:e .ikgdtksm3.,g 9:k1z(rbaierude.

  How much heat (in joules) is required to raise the temperature of 30.0 kg of wa gooj7p;6 +p)jr v zvznq/3g8tter from 1pv8nt/ +6gzzvq )7o3; prjgo j5 $^{\circ} C$ to 95 $^{\circ} C$ ?    $ \times10^{7 }\,J$

  To what temperature will 7700 J of heat raise 3.0 k2;yrf :q c2/z n:y.6dbke4waaqn2 vdig of water that is initially qndy/i fnqwcy4v62.be rk; z a:a22d :at 10.0 $^{\circ} C$ ?    $^{\circ} C$

  An average active person consume).zchjbi / r.ps 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 British system 1t9nb77jv iqf al,zz 1of units. One Btu is defined as the heat neededq7at1fji1n zz 7,b9lv to raise 1 lb of water by 1 F $^{\circ} $ . Show that
1Btu = 0.252kcal=1055J

  A water heater can gel dk *ak+v0olq- -ke5tnerate $32,000\,kJ/h$ 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 10w/- e3unp8egsywui4obx 2 ds0 an0aW. Estimate how long it will take to heat a cup of soup (ap0euase3 0 gs1do -y4axi w0/8nnwu 2bssume this is 250 mL of water) from 20$^{\circ} C$ to 60$^{\circ} C$ .    min

  How many kilocalories are gen knapr7s*venuo11 *j )erated when the brakes are used to bring a 1200-kg car to rest from a speed of kj1a r*7)1nuoe* nsp v$95\,km/h$ ?    kcal

  An automobile cooling snez6 7s3 .i 9uvmgtu.wystem holds 16 L of water. How much heat does it absorb if its temperature riwngvs.u76.i9 e 3tzm uses from 20$^{\circ}C $ to 90$^{\circ} C$?    $ \times10^{ 6}\,J$

  What is the specific heat of a metal substance if 135 kJ of hedy (t-sdhl2l,5ldmh 0enj94mk1 h( hhat is needed to raise 5.1 kg( yd419(l,nlmh-0 e dmhkhh5ds lhjt2 of the metal from 18.0$^{\circ}C $ to 31.5$^{\circ} C$ ?    $J/kg\cdot\,C^{\circ} $

  Samples of copper, aluminum, and water experience the same t*kdu-j gfg 3n)emperature rise when they absorb the same amount of heat. What is the ratiuggfn k3)jd *-o of their masses? [Hint: See Table 14–1.]$m_{Cu}$ : $m_{Al}$ : $m_{H_2O}$ =    :    :   

  A 35-g glass thermometer readsr 3bttc085 2fbki/pfv 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 cop-d ;fpmu;yv jzjy k8xg+:s3l;per 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 (mass =ef h6cz+9 lasa6rm-e1 $0.4\,kg$) 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 sub0ef rxn+e5+:n bk0/sp 7wwvhgstance is heated to 330$^{\circ} C$ and then plunged into a 105-g aluminum calorimeter cup containing 165 g of water and a 17-g glass thermometer at 12.5$^{\circ} C$ . The final temperature is 35.0$^{\circ} C$ . What is the specific heat of the substance? (Assume no water boils away.)    $J/kg \cdot C^{\circ} $

  How long does it take a 750-W coffeepot to bring to a boil 0.75 L of wa;oa zslydh8:;vrd 9 w3ter initially at zrdhs839 dowyl:; a;v8.0$^{\circ}C$? 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 mea 8 wvd+tsvnlo98s.nd 2surements. A 15-g sample of the candy is allowed to dry before putting it in a bomb calorimeter. The aluminum bomb has a mass of 0.725 kg and is placed in 2.00 kg of water contained in an aluminum calorimeter cup of mass 0.624 kg9.8slvdt+v8nd2 wsn o . 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 irond(na+7 b8xdyo,/vv-kmlm, ;wu b1slxjc3el/ 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 has a speed of; fnrn mm an)g.mi,i tt+ib37. $6.5\,m/s$ 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 isttg 5h4tcogly moe-:9l.rdd :1t 4)bd defined as the amount of heat needed to raise its temperatu: glty :dgtbm )44l9ohdt r1tedc-5.o re 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 th:3 967v xph t3wn2nu.z ikeyugat is initially at 20$^{\circ} C$?    $ \times10^{6 }\,J$

  A 0.095-kg aluminium sppq-+6ed u yn4p2o s.yyhere is dropped from the roof of a 45-m-high building. If 65% of tuo.dqy2pny6e4 y+- s phe thermal energy produced when it hits the ground is absorbed by the sphere, what is its temperature increase?    $C^{\circ}$

  During exercise, a person may give ofym8b k qz/ 1s9nzi w*gqxd* +e6scy55vf 180 kcal of heat in 30 min by evaporation of water from the skin. How much water has b i8snms9de55zz *b+ *xwqkvc6q/ y y1geen 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 meltng mwxbb- b8;5 csk09/pr(v sbing point is dropped into an insulated container of liquid nitrogen. How much nitrogen evaporates if it is at its boiling point of 77 K and has a latent8 bb9;v psb/bk0r5(m nswcx-g 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 tak5ae 7(g7cqygq+a m drc0zw7m,en from 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 kg ,nfs5wk ;pcj; contains 830 kg of water at 18$^{\circ} C$. A heater supplies energy at the rate of $52,000\,kJ/h$ How long does it take for the water
(a) to reach the boiling point,$\approx$    h (Round to one decimal place)
(b) to all have changed to steam?$\approx$    h (Round to the nearest integer)

  In a hot day’s race, a bicyclist consumes 8.0 -0jpzzq . cir0L of water over the span of four hourrc.0j -i z0qpzs. 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 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 10oxn4*e 45 1f vsrat;bw:hes;r0$^{\circ} C$ 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 /51o 7ef,qw x msnnng*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 travelinzt/eosu5 6:+2q ;i1j g xrmwqvg 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 x jcbea, ta .b095j4fn$6.4\,m/s$ glides to a stop. Assuming the ice is at 0$^{\circ} C$ and that 50% of the heat generated by friction is absorbed by the ice, how much ice melts?    g

  At a crime scene, the forensic investigator notes that the xi x f0na6x4:i8.2-g lead bullet that4ix0:6na x xfi was 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 dit4kliyf5i sv(d-x h., ameter 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 conduct e )axrk;+kr /,wkw2ynpxqe,* ion in Example 14–10, assuming that there are strong gusty winds aak/ x* qe2,wr)xerwpnyk ,k+;nd the external temperature is -5$^{\circ} C$   $ \times10^{4 }$ W

  (a) How much power is ra70+ufq oz )dyadiated 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 cond/q wfa3y 2 l2p*twxs:wuction from the blood caw*f 3q 22:axs/wyl twppillaries beneath the skin to the 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 sar1mxcwbpc s +)tx4td u:w5e)8p41leide, share a 12-cm-thick brick wall. Because oe41wa1t 4:b)ctmu)slcxe+ d pw8 5pxr f 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 tdh26hhvx )1iro melt a 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 satocdj0+)eeq2; no nt0me length and cross-sectional area are attached end to end (Fig. 14–18). The copper end is placedtt + e;nj)02 0oqcoend 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 whic:l,u+/oa 0 /lg5rmibxph vn* eh the whole Earth receive 0x :mao5rlub pve*//g,ihln+ s 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 is dissipated through a glass 8gemjl4-ss 8a bulb that has a radius of 3.0 4emg-8assl j8 cm and is 1.0 mm thick. What is the difference in temperature between the inner and outer surfaces of the glass?   $^{\circ}C $

  Suppose the insulating qualities of the wall of a house come mainy.(:x/ 9wtkvwfd*a+xi( 2fu gfs c6zfly 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 of heat loss through sux+f g(yfu 9d*/ vscafikf.w(z6:twx2 ch 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 glass /l2wb4jw(tuo-jn+ no separated by an air space, Fig. 14–20. (a) Show that the rate of heat flow through such a window by conduction is nbwu4+tol-( joj2/ wn 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 0r3viyiuahm*cs6 dr ;m f8+0)w$^{\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 liquid at ywu1j70voej))t .pd q5$^{\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 muca7g n4/fiv:ffh thermal 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. (Approximateg7 f4fa: /ivfn the ocean water as pure water for this estimate.)    $ \times10^{ 15}\,J$

  A 15-g lead bullet is tested by-wb) ix)3zn ib firing it into a fixed block of wood 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 sy bw -zx3n)ib)istem 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, xmhz;qlm(:dg* 5(tgb assuming it to be a perfect emitter agh xlt(*5;qm bzm:gd(t $T\,=\,5500K$ 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 pev:g8 w,qzk r/arson 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 rolls off the top of a cliff and fk)ax 2accsnw4*ok5 v-alls a vertical height of 140 m beforek)vc2kxw-ao 5an*sc 4 striking the ground. Estimate the temperature rise of the rock if 50% of the heat generated remains in the rock.    $C^{\circ} $

  A 2.3-kg lead ball is dropped0)bcqs qo3n;nc6 g x+n into a 2.5-L insulated pail of water initially at 20.0ncq x +)nsg c;b3oq0n6$^{\circ} C$. 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 tot ke 6gr7/3rqjgal surface area e6q/g7k jgrr3 $1.2\,m^2$ 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 anx pemjn2:asf;xl2+ (f average 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 -8zltzpgs56 x can be conducted from the interior of the body to the surface. Assume that the thickness of tissue is 4.0 cm, that the ski z pls-6z8g5txn 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 pq3kcy) j /9*)wgu hh(ut mqw.ox89eyof air) and at qcwhu ey.*83(u)k jxw9)/p9mqhg oyrea $410\,m^2$ 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 trn ni0 0ql*djv1y :bh1p xo7p;iaveling 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 fcdkmckm 5m0q6g./g a+ m 0hx5prom the leaf to calculate how much water must be transpirkk d5/acq6h xmm 5mmc. 0gpg0+ed (evaporated) by the leaf per hour to maintain a temperature of 35$^{\circ} C$.    g/h

  An iron meteorite melts wheng4::d qhy,oih it enters the Earth’s atmosphere. If its initial tempehd qg o:y4:ih,rature 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 increases5mekd5p 1f nm6 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 squass7 vyouq9b() e:/ju unh (Fig. 14–22), two people hit a soft rubber ball at a wall until they are about to drop due to dehydration and exhaustion. Assume that the nu(subeou ) :jv 9q7y/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 result when equal ma,0my-pcuz1i9b+,qw +wfhm t r 1jb n5hsses of ice at 0$^{\circ} C$ and steam at 100$^{\circ}C $ are mixed together?

  In a cold environmentn+6vey r)y.d wk t6 ;k7bo/kch, a person can lose heat by conduction and radiation at a rate of about 200 W. Estimate how long it would take ybvkd/e; 6.y n7+ct kkrwoh6) 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, th/)cctl;6shk (s v*a weere is “no hot water” left in the 50-gal (185-L) water heater. This suggests that the t c/v;ktsac) s6hwel*(ank 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 sury2ad9 weukrc,ic1;t 8face of a 60-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.    $^{\circ} C$