What happens to the work done when a jar of orange juice is vigorously shan+d76s*blvw jken?

When a hot object warms a coole /vhjjy 7exr(+ t,;68hb zrwvor object, does temperature flow between them? Are the temperature changes of the b txoj8(h r7 vrzweyvh+,j/6;two objects equal?

(a) If two objects of different temperatures are placed in cozsn* ym .x40rhntact, will heat naturally flow from the object with higher internal energy to the obje hm4yznr0s.x *ct with lower internal energy? (b) Is it possible for heat to flow even if the internal energies of the two objects are the same? Explain.

In warm regions where tropical plants grow but the temperature may drop bo nzd 4opjv 89k0johu9-g9ae22 h ox8welow freezing a few times in the winter, the destruction of sensitive plants due to freezing can be reho28a9u-ok0on 994x2evg phw j zd 8ojduced by watering them in the evening. Explain.

The specific heat of water ; :dpc9j2;; iiisxq acis quite large. Explain why this fact makes water particularly good for;ip9;qd;2 icjax:is c heating systems (that is, hot-water radiators).

Why does water in a metal canteen stay cooler if the cloth jacket 4 hm(jvx k,6uzvpr +g7surrounding the canteen is kept uxpghvz r6,vm(7j+ 4k moist?

Explain why burns caused by steam on the skin pee:0bpm9 3 4vm w0xd(1wfdsmo :p3l kare often more severe than burns caused by k13e sx wb :0mp3p:e0p4dowl v 9dfmm(water at 100 $^{\circ} C$ .

Explain why water cools (its temperaturdl m2*1py8zy l)d+kqge drops) when it evaporates, using the concepts of latent heat and internal energyqll2ym y*)z dp8gd+1 k.

Will potatoes cook fao v:p 7y-rzw.ester if the water is boiling faster?

Does an ordinary electric fan cool the air? Why or why not? If not, why use0zqd i kc;0tb.mi0p,m it?

Very high in the Earth’s atmosphere, the temperature ce)jcol6v s1+wan be 700 $^{\circ} C$ . Yet an animal there would freeze to death rather than roast. Explain.

Explorers on failed Arctic expeditiol - a7 jrqn4scrj**jb6ns have survived by covering themselves with snow. Why would they do a -4jjjqs 76rb* lnr*cthat?

Why is wet sand at the beach cooler to walk on than dry saz5 ;/s-8 v7.io-fsnzqxnmyimnd?

If you hear that an object wgc y:ip8/q3k +eb. rmhas “high heat content,” does that mean that its temperature is /:m+ rp kib e.cg3ywq8high? Explain.

When hot-air furnaces are used to heat a house, why is it importanga hw:ee; gbu )p)0t4rt that there be a vent for air to return to the furnace? What happens if thisbe) :rt4eh;aug wg p)0 vent is blocked by a bookcase?

Ceiling fans are sometimes reversible, so that they drive the air u 4t/igf,)qt kdown in one season and pull it up i/,k4tu) gf itqn another season. Which way should you set the fan for summer? For winter?

Down sleeping bags and parkas are often specified as so many inches or ceniz-r- e8 jr/nltimeters of loft, the act8r-/zjelrni- ual thickness of the garment when it is fluffed up. Explain.

Microprocessor chips have a “heat sink” glued on top that looks like a seo:)d x-u11*1akvw jwljnt.p g ries of fi-o:w *1 u gtnkv)awlpjd1.1jxns. Why is it shaped like that?

Sea breezes are often encountered on sunny days at the essul 1,b 68skshore of a large body of water. Explain in light of the fact that the temperature of the 8su6esl1ksb , land rises more rapidly than that of the nearby water.

The floor of a house on a foundation under which the air can flow isku8yy)( * /qhbybno, w often cooler than a floor that rests directly on the ground (such as a concreteq)bywy 8yu* b,n/koh( 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 reado:-l(u wr)ayv,c3e ikings are always taken with the thermometer in th)li-c3k( a,o:ru w vyee shade.

A premature baby in an incubator can be dangerously cooled even when thb t6*hi7bhvpp u 81ry.e air temp .6bpit yhph1*87urvberature in the incubator is warm. Explain.

Why is the liner of a thermosyn 95k 0ukb(ju h08ujk6ik( ifmrbe 0: bottle silvered (Fig. 14–15), and why does it have k0u:bi jnbui6mek hr(yj0u05k8(9 kfa vacuum between its two walls?

Imagine you have a wall that is very well insulatdc3. dvy;5qx6.gu my zbm*u+led — it has a very high thermal resist;m+ y5yxd*ugu .ldvzqb6c.m3ance, $R_1$ 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 pr x8evv8s.:h c1 qd1utnocesses: (1) ventilation 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 redux 1dt.n881v sc ueq:vhce which of these heat losses? Explain in detail.

A piece of wood lying in the Sun absorbs mo;evlx uax: *s+re heat than a piece of shiny metal. Yet the wood feels less hot than the metal when you pick it v+e:lax*; sxu up. Explain.

The Earth cools off at night much more quickly when the weather is clee f) j*vl-(f6 wrimez.ar than when c el6v (*if )wj.rmzf-eloudy. Why?

An “emergency blanket”j spv69:c 3xk*ix 9u0,q4pd rgprrip1 is a thin shiny (metal coated) plastic foil. Explain how it can help to keep pu4, q 3p1riri:x0r9jdgs6cvxp p k*9 an immobile person warm.

Explain why cities situated by the ocean te)wrta*r b-k6 snd to have less extreme temperatures than inland cities at-s r)ra6k *wbt the same latitude.

  How much heat (in joules) is required to raise the temsd*yqxm w,1 uitwh ju64/ n:8hperature of 30.0 kg of water from 15jsx8q64h*td/,i um nwywu1 h: $^{\circ} C$ to 95 $^{\circ} C$ ?    $ \times10^{7 }\,J$

  To what temperature will 7700 J of heat raise 3.0 kg of water that is initialpbqt.mol dw5 4gw+*n (aiu8l(ly a 4.ow*lglwtnba(+i q85d (u mpt 10.0 $^{\circ} C$ ?    $^{\circ} C$

  An average active person r17kff, hax/us5, d) :m5ixaznld0 sxconsumes 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) 2g fv(1 tug1; pje,yld60frixis a unit of heat in the British system of units. One Btu is defined as the heat needed to railt1(, vu1y2 x irg;06ejpdfgfse 1 lb of water by 1 F $^{\circ} $ . Show that
1Btu = 0.252kcal=1055J

  A water heater can generateh :n7 j6n5 h(bwi,kzyh $32,000\,kJ/h$ 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 35cdg,cir+ u0wa. (fchg. j 0yu10 W. Estimate how long it will take to heat a cup of soup (assui0gu01 , jay.cf( .cdrcu+whgme this is 250 mL of water) from 20$^{\circ} C$ to 60$^{\circ} C$ .    min

  How many kilocalories are generated when dms0sb07 4sdyfwd v cg3y4a(4the brakes are used to bring a 1200-kg car to rest from a speed d7yv44fsg0w0d4(sdby c s3m a of $95\,km/h$ ?    kcal

  An automobile cooling system holds 16 L o) m5ymffk +wgtvqy( -i if);9uf water. How much heat does it absorb if its+vw9 ki5 yf)ym-()u gtm if;fq 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 needeye1e oo-mzr/0- i8xmk zg zc:fvd;w5; d to raise 5.1 kg ofe-i;:8f meg50 /wcmzvzzd r;ky1 xo-o 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 tempera pq6t2vb (uxx:g*u vb9ture rise when they absorb the same amount of heat. What is the ratio of their masses? [Hint: See g6u9 xq:vtuxb(*p2v b Table 14–1.]$m_{Cu}$ : $m_{Al}$ : $m_{H_2O}$ =    :    :   

  A 35-g glass thermometer rea3gxvd7*jm1erh40*v z 5l e nemds 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 :8 ds k2x+ xbr4.l.p( kmihwlbwhen a 245-g block of copper at 285$^{\circ}C $ is placed in a 145-g aluminum calorimeter cup containing 825 g of water at 12.0$^{\circ} C$ ? $T_{eq}$ =    $^{\circ} C$

  A hot iron horseshoe (masay 4g1p(c l ytm82rc)xet*i6qlj s68j s = $0.4\,kg$) 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 j94mwum9t 4ovheated 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/ph s-op 1e f(,qyb5b-hjma;m a 750-W coffeepot to bring to a boil 0.75 L of water initially ahp-ba ojs,ebq - y/1 h;5fmmp(t 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 of 75 g of candy from the following measure7uq pz kb+jy,8ments. 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+uzk,bj8 py q7 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 z0yj/dwfla xgj-3c+5180$^{\circ} C$ 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 hakt81p6(x ur66xlfr,pebkm7w mmer 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 a6in qdejwc04rg uudc(3o70w4n object is defined as the amount of heat needed to raise its 3r 47du0qn(0cujgd ewc4oi6 wtemperature 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 neede, tm0bsf6nm1dd to 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 45-m-high builrzj rsk: c;ek +2fx3y2ding. If 65% of the thermal energy produced when it hits the ground is absorbed by the sphere, what is its t;kfjk:e2y rc3zr 2sx+emperature increase?    $C^{\circ}$

  During exercise, a person may give off 180 kcal of heat in 30al3 3 lm; om9dgdgd i-g7cm67w 1jx8yi min by evaporation of water from the skin. How much water has bg3l 3agm86g;wxyd o7c7- jmil9 d1idm een lost?    kg

  If $2.80 \times10^{ 5}J$ of energy is supplied to a flask of liquid oxygen at -183$^{\circ} C$ how much oxygen can evaporate?    kg

  A 30-g ice cube at its melting point is dropped into an insulated contaxg/a 5-tm 88ot1v1ki:npabzd iner of liquid nitrogen. How much nitrogen evaporates if it is at its boiling point of 77 K a51n ma- 8ivz/ago1 dkx:8 ttbpnd 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 fry 2 g3/ 51gtfik) s-hqogk.qxyeezer 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-ms .o+:spqy)e ap gu: 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 L of water over the spz+ 8i5 drm)ifb o. h-nwjg422hq(ckyzan of four hours. Making the approximation that all of the cyclist’s energy goes into evaporating this water as sweat, how muc4.8zf) mcqgibrjno- h2wy (zdk+2h 5ih 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 ati+65,.mraev fqjri 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 mercury is 9n6c+t /1 mur xjoade*r e*dg-$138\,J/kg$$\cdot\,C$ Determine the latent heat of fusion of mercury using the following calorimeter data: 1.00 kg of solid Hg at its melting point of -3.9$^{\circ} C$ is placed in a 0.620-kg aluminum calorimeter with 0.400 kg of water at 12.80$^{\circ} C$ ; the resulting equilibrium temperature is 5.06$^{\circ} C$ .    $ \times10^{ 4}$ J/kg

  A 70-g bullet traveling at tp yhg*x,m(. 53jm ab9 pyqx-n$250\,m/s$ 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 m1bmj:r gxu o1* i:wx8e b+zuk)oving 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 ;j58 hl0rmkddif05tw ,thtc-investigator notes that the 8.2-g lead bullet that was stopped in a dootd5; ki0hchlfmdrt-08j wt5,rframe 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-l 0ek ,y./0mtd1xru7d3xr uaz,)yk rvkong 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 condu +t hoj(tz6*pdction in Example 14–10, assuming that there are strong gusty winds and the external temperature is -jd(opt+ h*6 tz5$^{\circ} C$   $ \times10^{4 }$ W

  (a) How much power is radiated by a tungsten s krh im q3xh3s1q;e4 dy.bg+a8phere (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 cohy1 -u4ivloji *z.nm .nduction from the blood capillaries beneath the skin to the body’s surface area ofnzu-iyomi v41. h.jl* $1.5\,m^2$ 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 wao sn;:l s(/lg gm8sg9zll. Because of a number of 100-W lios mlz/s(lsgggn; 9:8 ghtbulbs 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 Su/x56otsn 3aoex dx 34y7k(vwe n to 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 s) 8ybs(il*z rhame length and cross-sectional area are attached end to end (Fig. 14–18). The copper end is placed in a furnace maiir(h*8zy ) blsntained 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, )p hb -met9c* s8+hfgoestimate the rate at which the whole Earth receives energy from the Sun. +thmg e h*s-pc8)9bfo    $ \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 g8 brnpy 0kr5b 5;/bqsa glass bulb that has a radius qr; k/bn5pbg5 y08b rsof 3.0 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 insulatingacjma,+p.v y nx :;4xy qualities 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 of heat loss through such a wall, if its tpvay; : xn j,cx+.my4aotal 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 separated by an air space, Figmxy6 3 uaj1d9qqdv*. w. 14–20. (a) Show thauj9qaqd 3dxmv1y *w6. t 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 amlzgn i1r.mm6 g8g+m 9t 0$^{\circ}C $ to melt when it is placed in a carefully sealed Styrofoam ice chest of dimensions $25\,cm\times\,35\,cm\times\,55\,cm$ whose walls are 1.5 cm thick? Assume that the conductivity of Styrofoam is double that of air and that the outside temperature is 32$^{\circ} C$.    $ \times10^{4 }$s

  A soft-drink can contains about 0.20 kg of 1cugv((bot vp4)ag2m 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 th)tp5 64ygszgdxzy lzgv i1mru89ls 48-0y i2rermal energy is contained in the world’s oceans, estimatr g zl4iy8ryd5 sz i80l1vm 249yps -xt)zug6ge the heat liberated 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 ixh t7an17l i(mrs(08kd5pciw nto a fixed block of wood with a mass of 1.05 kg. The block and imbedded bullet together absorb all the heat generated. After ther5(xk da p07lr7 cst1i nihm8(wmal 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, assuming it to be:csl r:m/ m-7yys bgb u7;.zpl a perfect emib usrmc-l:yz/p7lm.7 gy; : bstter 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-knhp b59v:fcwx /+ h5ekg 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 rolls off the top of a cliff andv ;jm/lzyd)dmp);d n4 go:a)m falls a vertical height of 140 m before striking the ground. Estimate the tem4mdvd;zj) /a y o)m)m:nl;dgpperature 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 ajx 2c)am0 bvm2ao z6p, 2.5-L insulated pail of water initially at 2om6 ajm20ac 2,v)bpzx0.0$^{\circ} C$. 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 gsl/ ech:wh-0el/y3ef py.* w cm thick with total surface area y* g h:-p0ly wlee3ewsfc/./h$1.2\,m^2$ 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 ratzg2 z m:c.zhfjr/n6 a,e 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 of the bsof d;+jt fs9+vfavi+0: gk.i9fpl z+ody to the surface. Assume that the thickness of tissue is 4.0 cm, pdaf09 i 9vf;fkg + vi+os.fs+:lzj+t that 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 c43 y;sr y1+ fi ba-r1nwtu;eqem thick (assume conductivity of air) and area 1nu e3fyryi ew4r;s tq+;-b 1a$410\,m^2$ 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 afh. moq8 s56na86 j6xue+ mejit $220\,m/s$ 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 int+rk 9 nv9zxym7a9imx8o account radiation from the leaf to calculate how much wa9v kz9nrya9mimxx +87ter must be transpired (evaporated) by the leaf per hour to maintain a temperature of 35$^{\circ} C$.    g/h

  An iron meteorite melts when it ev6nke9:fnd/scg31buq-c i i /nters the Earth’s atmosphere. If its initial temperature wasu1 c/s9-63k:f ni/dq c gebnvi -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 Earthq5 9g 5xbtx9sk’s crust increases 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)c 9ou8 dlbluhbm:w 4ttl38c; people hit a soft rubber ball at a dlw3hutb:mot ;8c8 u9 )bllc4wall 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 result when e /,8iyg 828u4zbstmv 8x vj5/wa tzwjjqual 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 radiation rgzeveq s2367 at a rate of about 200 W. Estimate how long it would take for the body temper ze26vge3q sr7ature 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 inmjq2a-j zq8l)sn:ds d ;h2s-b the 50-gal (185-L) water ms-bsj )l : ;jdsz-2qq2a8d hnheater. This suggests that the 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 60z ug:(vx9j t.zqi4an:-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.    $^{\circ} C$