What happens to the work done when a jar of orange juice is vigorously shaken?k*.l7)wiap3 ab z(4f5h u yafota(sc(

When a hot object warms a cooler object, doec4te9)l)wvj:cz 9wy+tu z ;yw 2h,fo cs temperature flow between them? Are the temperature changes of the two objects e owzy,9f ty v l:;cctw h)uw2j4+)9zecqual?

(a) If two objects of diffev19 1lqx) hmlpaoq5m wa 7 ,,6l8kathcrent 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 ltaw 5h a6kcpv,q ,8l1ah79m 1m ql)xoif the internal energies of the two objects are the same? Explain.

In warm regions where tropical plants grow but the temperature urj n./fd boi7zf1k t2bz*.x1d28z3q+e yobr may drop below freezing a few times in the winter, the destruction of sensitive plants due to freezing can be reduced by watering them in the eveningrfz7k.jzu r +2t8b i2* yo1 db.zxfe/d3onqb1. Explain.

The specific heat of water is quite large. Explain why thub. u*(usnby*mx*. fk is fact makes water particularly good for h(mu.x *b*buf*n y.ukseating systems (that is, hot-water radiators).

Why does water in a metal canteen stayxs/ u+u. ;k arsevnaxowh:zy7 7f4.4j cooler if the cloth jacket surrounding the canteen is kept moixxh +su s/an.;y4ekwu77o a.zjf4 r:vst?

Explain why burns caused by steam on the skin are often more9wvvd;m,xf.n jbtco*gz/g) ep 4-v - z severe than burns caused by watee-mw dgb gp4xf,9vvv;tc o/ -n*)j z.zr at 100 $^{\circ} C$ .

Explain why water cools (its temperature drops) whr7(,f2 w pxho nuxo:l*en it evaporates, using the concepts of latent heat andlxu ,(h :xo7pn*f2rw o internal energy.

Will potatoes cook faster52xp63(jni: z:iuixl)w -jxrotufg4 if the water is boiling faster?

Does an ordinary electric fan cool the air? Why or why nglb a6 zzy)+a 1b(tq(xot? If not, why use it?

Very high in the Earth’s atmosphere, the tem9c,e- m*g okegperature can be 700 $^{\circ} C$ . Yet an animal there would freeze to death rather than roast. Explain.

Explorers on failed Arctic expeditions have su(rx,f h.mws:j rvived by covering themselves with sns .rxh:mj,wf( ow. Why would they do that?

Why is wet sand at the beach cooler to walk on than dry sy*t9 ;ugygdrofm1oukf(- x51.r no 4 jand?

If you hear that an object has “high heat coqvh,ksl:s p ,sg0uz 3( z-yy wp6n7am0ntent,” does that mean that its temperature is hig h0nv:s-,yu 67(3zz,as yw0mq splpk gh? Explain.

When hot-air furnaces are used to heat a +nkhdho4ing ,d5ye0; house, why is it important that there be a vent for air to return to the5,4dnkh;yg0 dni h+e o furnace? What happens if this vent is blocked by a bookcase?

Ceiling fans are sometimes reversible, so that they drive the air down in one sd7 .969y x6kyh d vf/hoi1hgbbeason and pull it up in another season. Which way should you set the fan for summer? For win b h d7byo6996y.dkhhvfxig1 /ter?

Down sleeping bags agpiyb+ 1mj gkh 4w2*6qnd parkas are often specified as so many inches or centimeters of loft, the actual thickness of the garment when it is fluffed up. Explaiiwq1yjh6p gbk * +2mg4n.

Microprocessor chips have a “heat sink” glued on top that looks like a servb p u92wy4mj x3.*0jxvjl9ccies of fins. Why is it shaped like thjjxxl c 9cmj.*v 049wp2 3uybvat?

Sea breezes are often encounteredze+ k(1c vx9ge on sunny days at the shore of a large body of water. Explain in light of the fact that the temperature of the land +x1g 9ve(zeckrises more rapidly than that of the nearby water.

The floor of a house on a foundation under which the air cmzhm- / kdgm54op5aglh9 :i 5kan flow is often cooler than a floor that res: 4k-gi ap9mmgo5z/ h 55mkdlhts directly on the ground (such as a concrete slab foundation). Explain.

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

Explain why air temperature readings are always takgp bgb mgv -q.4yb46;zen with the thermometer in the shab6q -z4bg.gmbv;y gp4de.

A premature baby in an incubator can bep4vfa )fi-4e :vb emp/ dangerously cooled even when the air temperature in the incubator is warm. veppf 4fv4a:b)em /i- Explain.

Why is the liner of a thermos bottle silvered (Fig. 14–15)k7 (,bxy-oiv9r9ok wa, and why does it have a vacuum between its yikok9ar ,( o7 vxw9-btwo walls?

Imagine you have a wall that igt;5jbalh8jc2f; ch )b5+pl1/ tybl ys very well insulated — it has a very high thermal lgb5+j c8 /; b)lh5yjf ;a1byt2hclptresistance, $R_1$ 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) venp:+ay7d qnm(ptilation around edges; (2) through the frame, particularly if it is metal; (3) through the glass panes; and (4) radiation. (a) For the first pnyad7( +q:pm 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 than a piec2 ++1.;bpnu: aa uoa6yddn tace of shiny metal. Yet the wood feels 6b21ayd:d ; a +aoanu.c+n uptless hot than the metal when you pick it up. Explain.

The Earth cools off at night much more quickly when the weaey n*nxpl/12g ther is clear than when cloud e*gp/ ln21xyny. Why?

An “emergency blanket” is a thin shiny (metal coated) plastic fo 6 2qdezrk. ftuu.*vl*il. Explain how it can help to keep an immobile . kt2v*e.*luz6qfrud person warm.

Explain why cities situated by the ocean tend to have less extreiru 9s4o0t6h1qh; jv eme temperatures than inland cities at the sam;t9jhoh0i14v ru qs6e e latitude.

  How much heat (in joules) is required to raise thec11 dd: cv0l7(r 6mv .jjbnncm temperature of 30.0 kg of water from 1516nvcmc( d7 0c.rvnjjdlb1m : $^{\circ} C$ to 95 $^{\circ} C$ ?    $ \times10^{7 }\,J$

  To what temperature will 7700 J of heap. .jjs3i lai:e fp7i0t raise 3.0 kg of water that is initially at3pi.l0seap:i.7 i jfj 10.0 $^{\circ} C$ ?    $^{\circ} C$

  An average active person consumes about 2500 Cal a day. brxp( dh +jd 17s.g/kj
(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 (4-chf,)4z ,wma2ouch y: s nplBtu) is a unit of heat in the British system of units. One Btu is defined as the heat needed to raise 1 lb of water by 1czmhl4, 2u -h s:oanywfp4c), F $^{\circ} $ . Show that
1Btu = 0.252kcal=1055J

  A water heater can generat ) ibhp-mfl.);rh 6ojue $32,000\,kJ/h$ How much water can it heat from 15 $^{\circ} C$ to 50 $^{\circ} C$ per hour?    kg/h

  A small immersion heater is rated at 350 W. Estimate how lzmc0:-(mla 6dzaj 3 nbong it will take to heat a cup c azzlm nb a-6(dj:30mof soup (assume this is 250 mL of water) from 20$^{\circ} C$ to 60$^{\circ} C$ .    min

  How many kilocalories are g1 *k6t6hn z;kp. ngqcqi.ca,gqu 5a/bf7h q5yenerated when the brakes are used to bring a 1200-kg car to /kuqf.* gzt5q6aiq1 kc7.; p cnhnq 6hybga5,rest from a speed of $95\,km/h$ ?    kcal

  An automobile cooling system holds 16 L of water. How mu wjjyokb/z+h 9i :f+p1 iy60lgch heat does it absorb if its temperatureb/ y0hg16k jipowfl:y z+9i +j rises from 20$^{\circ}C $ to 90$^{\circ} C$?    $ \times10^{ 6}\,J$

  What is the specific heat )78tls*nwje+e cy( kv of a metal substance if 135 kJ of heat is needed to raise+ y*e( 7ejn sw)klvct8 5.1 kg of the metal from 18.0$^{\circ}C $ to 31.5$^{\circ} C$ ?    $J/kg\cdot\,C^{\circ} $

  Samples of copper, aluminum, and wae:8tupvp 5gq1wj5,vr 8 ul nw1ter experience the same temperature rise when they abs jvgn:w5qr ,8upep1tu wl1v 85orb 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 readso;y.8eidm8c q 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 equilibrav y*t)qk8d3t7)apx ku :o+bl ium temperature when 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 (mass7/m7bri6n qis = $0.4\,kg$) 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 subsuwq65r pe :8t97pty jktance 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 t3/x sstc - gvrs3ww+8ho bring to a boil 0.75 L of water initiav/ hcrswsg8- +tx 33swlly 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 of 75 g of candy from the following m6()wqqsij+lh vqo: c2 easurements. A 15-g sample of the candy w 2 lci)q:ho+jqq 6sv(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 iron5flx -5i cwnrnxxo5a 59e3s 9j 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 spee6;fs*b4moe:c m) uoojd 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 amount of h6krh 780 wqseseat needed to raise its tempswrh807e s6 qkerature 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 1; vl+ w18lhuf 5 *k, s/lfzuwt7bw-zso6.50 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 b0r-x- s*fpp2rc dwe z:0+b faep6rrn5uilding. If 65% of the thermal energy produced when it hits the ground is absorbed bbaf 0 -rpr- *fp+zd0w6ecenx:2psr5r y the sphere, what is its temperature increase?    $C^{\circ}$

  During exercise, a person may givoq+/idvc + 8wse off 180 kcal of heat in 30 min by evaporation of water from the ski++s o8dw/qciv n. How 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 itv(g,a qfgtl- l +kmuf 47h*j2ls melting point is dropped into an insulated container of liquid nitrogen. How much nitrogen evapo- lu+2*tam7qlg gj ,(4fhflkv rates 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 freez.:qjnjh wvcj*u (ud6; er 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 water at 8xr+uh8 1ry 9*lecvzn 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 h*f + xeo(8m 0yv2jhxnspan of four hours. Making the approximation that all of the cycli*h820+j xoh v(xmynf est’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 100-y6 lthl;k,: pvhgxz 3$^{\circ} C$ 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 i cc(syzia,1m7.fb k 9kqe(-bks $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 a4. 1jdjg cjmgh2c(858v jtmy gt $250\,m/s$ 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 d4 y,1 sfu71ma90ynfcjcpe6 w$6.4\,m/s$ 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 thatj/z-nt j:qjgfh q881c the 8.2-g lead bullet that was stopped in a doorframe apparently melted completely on impact.njgj -t j8:z h8q/fqc1 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 aluminuh. 9l4+h- f weq-ii vryj;e8hj+ur,avm 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 conductions/m1 ouuv p xq,h-57ny in Example 14–10, assuming that there are strong gs/x7 uu qhnp5,o-ym1v usty winds and the external temperature is -5$^{\circ} C$   $ \times10^{4 }$ W

  (a) How much power is radiated by a3 buhmo+td ;k9ewxh*; 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 flu 2 .42lgdg h-jp)chaoye,.fh ows by conduction from the blood capillaries beneat2p. a,g2gfh hjeu)d -chy4.olh 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 side, share a 12-cm-thick /3h 7w7gv*de(i sjf aebrick wall. Because of a number of 100-W lightbul ai7 e g(vw/3f7ejdhs*bs 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 block odl c1dt /;h9 eue4)uvyf 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 alr,ts2y6rc))8 ph u)k pf-swqot/scb 6uminum rod of the same length and cross-sectional area are attached end to end (Fig. 14–18). The copper end is placed in auhc)/f)tr8 ytpo -qsrbs )w26ps6, kc 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, estima0 (ovl q+ldbr,te the rate at which the whole Earth receives energy from the ldvl (qo, r0+bSun.    $ \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 he d+8wc6t7:yr bdj4uvsat, which is dissipated through a glass bulb that has a radius of 3.0 cm and is 1.0 mm thick. What is the difference in temperature between the inner and outer surfaces of t:ws td6 crdj4bvy7+ 8uhe glass?   $^{\circ}C $

  Suppose the insulating qualities of the wall of a house come ma.3s0 1pqp3/va;sv nnk orz,u vinly 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 z snopn/1,rq.kv3vp ;v3usa0 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 ofv jr:5m;u9 +jf;sbm l m/yc8wm glass separated by an air space, Fig. 14–20. (a) Show tvmf bcyu;8mwm/5 ;:lr mj+ s9jhat 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 8 7ter7oj jgknz 0od6(tgj q98gqj5q/should it take 11.0 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 about 0.20 kg of li2luotzxt f s:, 3/yb2gquid 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 8r. ;-hoeb63:jynft svz ba6hoceans, estimate the heat liberated when a cre tv:36nh8f o.a hb-bzys; j6ube 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 firingzqs8+v veg m8m* tg1gt9vser0j,/2qb 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 system has a temperature rise j2m seve0+1qm/*v,g qzgt v rbs89 g8tmeasured 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 a perx +nrzu*hvj5c8 9dgwr1ppl+;fect emitteu5jr;w9xp z pg1 hcn*d+8vr+lr 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, h57/ks3i bazuw:n3gz9w uhzc 79 w l.ea 70-kg person may generate $200kcal/h$ Assuming that 20% of this goes into useful work and the other 80% is converted to heat, calculate the temperature rise of the body after 1.00 h if none of this heat were transferred to the environment.    $C^{\circ} $

  A 340-kg marble boulder re 9qs90e 8p:jvc ni;xoolls off the top of a cliff and falls a vertical height of 140 m before striking the gpnxe09; :v9 ecoj i8qsround. 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 dropped into1qb yc *j:xsex7w2)ty a 2.5-L insulated pail of water initially at 20.:bt1e7s*2xxcwyj )q y0$^{\circ} C$. 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 c,xw0v fr 5f5hsm thick with total surface areasv, h rfwf505x $1.2\,m^2$ 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 a j7 j* ohpm64o6:sebbrverage 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 conyz3i0ao5.pfp, 9y zk educted from the interior of the body to the surface. Assume that theoz faiz 0p p3y5.e,y9k thickness of tissue is 4.0 cm, 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 cm thick (assujql he4yq 2;(pme conductivity of air) and aylqq2 ;jh(p 4erea $410\,m^2$ 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 at+zle (fxt1saa di9 nz fb-v6,/ $220\,m/s$ 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 ray q3eq+ nzrm 6ts fv)20/lz:rxdiation from the leaf to calculate how much water must be transpired (evaporated) by the leaf per hol/+rz fv:6em0rs3q )zq 2yxntur to maintain a temperature of 35$^{\circ} C$.    g/h

  An iron meteorite melts when it enters the Earth’s h,0 b puv*.dntatmosphere. If its initial tempera*p., b0nuh vtdture 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 Eau-jhl d* 3x5. 5, nsc0g/k7zexvtuqp urth’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 people hit a so ;xqi,3bg:td iu(tk*oft rubber ball at a wall until they are about to drop due to db;ut, ix io:d*gk3tq(ehydration 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 whe ;mcnap ko8vz6 3*:zn 4mdsv/en 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 kns t ir;zg;,y9z(uj0conduction and radiation at a rate of about 200 W. Estimate howz(iur z,t0gns j9k;;y long it 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” lew*ua )mhxt8bb4r a65 kft in the 50-gal (185-L) water heater. This suggests that the tank has emptied and refilled wi* 5ak6x4 mbbu8arwh )tth 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 leql v6a1;w(p eightbulb 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.    $^{\circ} C$