What happens to the wo;j l j(d9iztutt7dv) iuwsso)w z73,(rk done when a jar of orange juice is vigorously shaken?

When a hot object warms a cooler object, does tempebw:. 7lfsdf+5j7 l ujn 1,nrso7kwi wztp)1c-rature flow between them? Are the t7lk1t,p71+) .src fn- i:5zwn lwsw foudbjj7emperature changes of the two objects equal?

(a) If two objects of different lp oc98,o * 9hahwgf;atemperatures are placed in contact, will heat naturally flow from the object with higher internal energy to the object with lower inac9,98po; laohwf* gh ternal 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 dhon2 s 3vx2r3may drop below freezing a few times in the winter, the destruction of sensitive plants due to freezing can be reduced by watering d33x sn2vr2oh them in the evening. Explain.

The specific heat of water is quite large. Explain why this fact makes water fv66lqv9l :*jhr ; pumparticularly good for 9*:f6lu;v mlv6 jrpqhheating systems (that is, hot-water radiators).

Why does water in a metal canteen stay i7i oc3z fhf yns0c4+:cooler if the cloth jacket surrounding the canteen is kept moist3hifo+7:nyc 0 is cfz4?

Explain why burns caused by steam on the skin are often more severe than burdtuj)bicmz9d *64/ vy5m9 lfjns cauldvb6tdm/j 5i99 ) 4yuc*fjzmsed by water at 100 $^{\circ} C$ .

Explain why water cools (its temperature drops) when it e 1pzh g.tu17luvaporates, using the concepts of latezup u.11thlg7nt heat and internal energy.

Will potatoes cook fknuw- )ztz08r 68* weezr0rweaster if the water is boiling faster?

Does an ordinary electric fanf7mvn 88)5glk(wjfxnx p87td cool the air? Why or why not? If not, why use it?

Very high in the Eary;q-hcp t- bc2th’s atmosphere, the temperature can be 700 $^{\circ} C$ . Yet an animal there would freeze to death rather than roast. Explain.

Explorers on failed Arctic expeditions p gfnmvmtogs(4uyk2d( /;/4khave survived by covering themselves with snow. 4/u(dgft/my2 o pvsgnkm(4 ;kWhy would they do that?

Why is wet sand at the beach cooler to walk on than dry89y prq2) t7jvqh)fkx sand?

If you hear that an object has “high zrqjy*b znx8;- 2fjz .heat content,” does that mean that its temperbny xrj.fzq;-2 z j8*zature is high? Explain.

When hot-air furnaces are used to hyfu 4h:ds4gkhd; j4kw6 ,t*rceat a house, why is it important that there be a vent for air to retudwk s4y hc u4,gjr;6tkd:*4fh rn to the furnace? What happens if this vent is blocked by a bookcase?

Ceiling fans are sometimesz+dgt+t :m b;kxq0 0qbj i9v+e reversible, so that they drive the air down in one season and pull it up in another season. Which way should you set the fan for :b qq09e zbx+g;+v+tt kij m0dsummer? For winter?

Down sleeping bags and parkas are of j- bi-5o1o .ut,qethty ijj44ten specified as so many inches or centimeters of loft, the actual thickness of the garment when it is fluffed 5 tjy1-b,i4oethj. utiqjo -4 up. Explain.

Microprocessor chips have a “heat sink” 7kt+ eznctvu 06j 0spehh/ wqbp +d7z5(z*/ckglued on top that looks like a series of fins. Why is it sha ecpjzk6 0hbd7z(0e //tcz+kn5qvuw hp7s+*tped like that?

Sea breezes are often encountered on sunny dabngah+px v1 *7ys at the shore of a large body of water. Explain in ligxp 7a h+nbgv1*ht 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 foun27 i+my;wm xjadation under which the air can flow is often cooler than a floor that rests directly on the groun; 7wix2+aym jmd (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 readhuldz 4ls ix:ijhg1 l47 gu(;,ings are always taken with the thermometer in the shad4; d, hsxuu(14igl:i hl 7glzje.

A premature baby in an incubator can 8l lfhgmx6 9imbu+ 2t)l0n:h fow9tw: be dangerously cooled even when the air temperature in the incubator is warm. Exlot mf9mf9+wb:l6ltx8 h hnig ):20uwplain.

Why is the liner of a thermos bottle silvered jku 6 b 0k,imy7mbx9r/(Fig. 14–15), and why does it have a vacuum between ixrm09 jyb6km/u7kb, its two walls?

Imagine you have a wall fmxk p5jf;8hzo 6 +ob)that is very well insulated — it has a very high thermal resistof m+o 85 jfkhxpz6b;)ance, $R_1$ 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 wi.dy.oi be+x 1i ciusynb,/h0.ndows by the following processes: (1) ventilation around edges; (2) through the fram1y i0yn h u.xciedio +s../,bbe, 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 mo 5/6wph pepvj34hac ,ore heat than a piece of shiny metal. Yet the wood feels less hot than the metal when you pick it up.p/v jhp,cwoa5 43ehp6 Explain.

The Earth cools off at night much morezgf ;ut a5 hj+ym*-2yr quickly when the weather is clear than when clou fj5agh+2m-yuryz *t;dy. Why?

An “emergency blanket” is a 22.y m3yq)q bqrtct 8zthin shiny (metal coated) plastic foil. Explain how it can help to )2yyc .r2qt3t b mz8qqkeep an immobile person warm.

Explain why cities situated by the ocean tend (c:s.+jz 9mh mfap1p6elzs;f to have less extreme temperatures than inland cities at the same latituz j z :;f+lcss9mmh a(e.f16ppde.

  How much heat (in joules) is required to raise the temperatu32mc 2 sno1 ghj29xe n3t:sdv7.ucuk vre of 30.0 kg of water fuj:9 vo.ke sxm h21us 2237ngccndtv3rom 15 $^{\circ} C$ to 95 $^{\circ} C$ ?    $ \times10^{7 }\,J$

  To what temperature will 7700 J of heat raise 3.0 kg of water that is +a*f h9 xm 15nlnyk3)m l2srrbzy5gb3: 9yaeiinitially at 10.0 5y9m9 b1lx3z f5rna+ri )k:2my yn ablg hs*e3$^{\circ} C$ ?    $^{\circ} C$

  An average active pershrbog(:s*q a7n13l s 5aot wv1on consumes 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 unijmgnzev/1.8 zgte(xqce+ pml+( wg +6t (Btu) is a unit of heat in the British system of units. O +gxn.+ +e8 el6pqc1gve/z mwtg(z m(jne Btu is defined as the heat needed to raise 1 lb of water by 1 F $^{\circ} $ . Show that
1Btu = 0.252kcal=1055J

  A water heater can ge/p gtt( kmy/,eg *s8kenerate $32,000\,kJ/h$ 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 long it wilwj +a-a)hs7aov(9l srl take to heat a 7 hjaoa a-+vr9lss)w (cup of soup (assume this is 250 mL of water) from 20$^{\circ} C$ to 60$^{\circ} C$ .    min

  How many kilocalories are generated when the 0k;jirrmza(ayi6k9/i e,) bo brakes are used to bring a 1200-kg car to rest from a speed of9 j)zii yo, kbrakrem; a/i(60 $95\,km/h$ ?    kcal

  An automobile cooling system holds 16 L of water. How m:m* *e1iue h*cc2fjla uch heat does it absorb if i lei*uhmcj:1f*e2 *acts temperature rises from 20$^{\circ}C $ to 90$^{\circ} C$?    $ \times10^{ 6}\,J$

  What is the specific heat of a metal substance if 135 k4res-.8i40 cw zwj5)slv fb rfJ of heat is needed to raise 5.1 kg of the metal from 18.efrfzw s)-sj 05vcb4wrl.84i 0$^{\circ}C $ to 31.5$^{\circ} C$ ?    $J/kg\cdot\,C^{\circ} $

  Samples of copper, aluminum, and water experience u)h9r td,/i1esi bz:b the same temperature rise when they absorb the same amount of heat.e1,zb :udhtsb) iri9/ What is the ratio of their masses? [Hint: See Table 14–1.]$m_{Cu}$ : $m_{Al}$ : $m_{H_2O}$ =    :    :   

  A 35-g glass thermometer readsr. 8gqud*m sy5 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 copper at xh e5 ;o6g 9(rhwslkl0pfnly)c0 ,yw5 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 c(:)bvwspaw8 = $0.4\,kg$) 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 heate:.h2n u)m yhgsd 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 bri8(co6d q4q 3do gucsiyzv 69.yng to a boil 0.75 L of water initially 8q9i .(uzdyy 6o63doqcg 4svcat 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 measurementsajx:iy2r v0 5d. A 15-g sample of the candy is allowed to dry before putting it in a bomb calorimeter. The alumx:0ij2davy5r inum 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 iro2zpi eq4j18iwcc tk(7 n 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 /cq m:*n0v s ydt/vdes,vg9xyn8x 8d9hammer 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 amowj dn9202erys unt of heat needed to raise its temp wn02 2yedsrj9erature 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 that is 4llcu ;;cbs;vf38fh yinitially at 20$^{\circ} C$?    $ \times10^{6 }\,J$

  A 0.095-kg aluminium sphereu:p 6pt,-da cjmplwk 9rq; 9 kis1-4de is dropped from the roof of a 45-m-high building. If 65% of the thermal energy produced when it hits the ground is absorbed by the sphere, what is4a 1pc6 rj-:tdkp9lmqse, w;u p-9 kid its temperature increase?    $C^{\circ}$

  During exercise, a person may give off 180 kcam;ken3 nkp(2 /guq* dpl of heat in 30 min by evaporation of water from the skin. How much water has been los2* pn;3/menqdpk(g u kt?    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 contke7qn j -u*h;painer of liquid nitrogen. How much nitrogen evaporates if it is at its boiling point of 77 K and has a latent heat of vapor; q eh7jp*nk-uization 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 thev96 jidsc d0q1q(;0g9kkx izj 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 contains 830 kg of 72, ifanw dzm4water 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 sw4f)on 2cek7 di6d k/cpan of four hours. Making the approximation that all of the cyclist’skw/4if6 7dcn od 2ke)c 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 atnnio dxrd 9-9r3vgc 0kew;.2f 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 mej.c1,/ 0/axd6nqfi muuv5ok .w,bytbrcury 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 atg syi.12zaa) yco s5p6 $250\,m/s$ 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 at3s1a f nz:rfd11-; an rnmw5fb $6.4\,m/s$ 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 8.2 hcp grt:/ r6yuvl +yr/nfd(e(7bq,e)-g lead bullet that was s/uln, y7r/h rf ec+yr qv(b6e( dt):gptopped 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 gx6q)2bfm z/ia 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 in Example 14–10, assuming to 5 qsbbzx;ud89 ei04khat there are strong gusty winds and the0x8 ebks 9u4;zb5qdi o external temperature is -5$^{\circ} C$   $ \times10^{4 }$ W

  (a) How much power is radiated by a tungstr .l l5xuck-s)en 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 20a nqjg7/6q9p2 a0mlhf0 W of heat flows by conduction from the blood capillaries beneath the skin to the body’s9qflqa6a n0g 7 h/pjm2 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-c0txa.qzs jatf(80 9 tm:z0wxwm-thick brick wall. Because of a number of 100-W ligzwmt 0 xf t08. (9asw0ajqtzx:htbulbs 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 bloc guwm,)cy0/eqk of ice at 0$^{\circ} C$ with a flat horizontal area $1.0\,m^2$ and thickness 1.0 cm? Assume that the Sun’s rays make an angle of 30$^{\circ} $ with the vertical and that the emissivity of ice is 0.050.    h

  A copper rod and an aluminum rod of the same lengthmhe12qytm2lnwc+w y 0/*xjq 5m )va1l and cross-sectional area are attached end to end (Fig. 14–18). The copper end is placed in a furnace maintained at a constant+mtmyyh wqwq0 )5c n2lel a12v*1 /jxm 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, estimaq0pgf9ssc7* h te the rate at which the whole Earth receives enehps97 0gc*fqsrgy 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 c*v1;8,tnk/uq a7fp t(t b)g dv+viu hW of heat, 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 anptvdkc iu)qt/b+g tvu8 1( * a,fv7n;hd outer surfaces of the glass?   $^{\circ}C $

  Suppose the insulating qualities of the wall of a horhv9 t0 xrq-((8q iruzuse come mainly from a 4.0-in9r 8u-ir((rzvt qx q0h. layer of brick and an R-19 layer of insulation, as shown in Fig. 14–19. What is the total rate of heat loss through such a wall, if its total area is $240ft^2$ and the temperature difference across it is 12 $F^{\circ} $?    Btu/h

A double-glazed window has two panes of glass sepk8u7mtwl3 p wa-f8hu*arated by an air space, Fig. 14 kufpt-w *hu883 7lwma–20. (a) Show that 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 shou.;h p7htnf m9zs4 z4728p0ijtskvz2br xy-hk ld 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 containz 8uk:bwd-t5g s about 0.20 kg of liquid at 5$^{\circ}C $. Drinking this liquid can actually consume some of the fat in the body, since energy is needed to warm the water to body temperature (37$^{\circ} C$). How many food Calories should the drink have so that it is in perfect balance with the heat needed to warm the liquid?    C

  If coal gives off $30\,MJ/kg$ when it is burned, how much coal would be needed to heat a house that requires $ 2.0\times10^{5 }\,MJ$ for the whole winter? Assume that 30% of the heat is lost up the chimney.    kg

  To get an idea of how much thermal energy is contained in the world’s oc0khx uvy7pzh5d eyn)ritfq;-4 . vt )5eans, estimate the heat liberated when a cube of ocean water, 1 e5)ztt pdy;70 n5q4hhy.)if-uvvkxrkm on each side, is cooled by 1 K. (Approximate the ocean water as pure water for this estimate.)    $ \times10^{ 15}\,J$

  A 15-g lead bullet is tested by firing it into a fixed block of wood with a massxstzb*d64df2wu; )ut of 1.05 kg. The block and imbedded bullet together absorb all the heat generated. After thermal equilibrium has been reached, the )d6ts wz;tbuu *2xfd4system has a temperature rise measured as 0.020 $C^{\circ} $. Estimate the entering speed of the bullet.    m/s

  (a) Find the total power rej/f 6 +tc6ydladiated into space by the Sun, assuming it to be a perfect emitter fdc6tle/ 6y j+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 pe2x m 16s:nydokgns/(frson 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 falsi cl4yo - p/i2:f(sgkd;+z alls a vertical height of 140 m before strikisgoi+; zkf aspd: -4(/il ylc2ng 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 droppedd yp 2ujgr:8 jfx,bf-xr4l olsax 31+6 into a 2.5-L insulated pail of water initially at 20.uf,-pbxsr8lj xlao :yjg1d3f2r+6 4 x0$^{\circ} C$. 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 am cnhbk 69ch*tl8 4xx. goose down jacket 3.5 cm thick with total surface are 4cl *n.th k9c8xmbh6xa $1.2\,m^2$ 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 metab;b-t ( 1o96cxbuttaajolism 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 intbdzif4r 9u1 gpq.s 0yb4:. jszerior of the body to the surface. Ass4 z. bupjsfiy s4bdq09gz:r.1 ume that the 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 17ly/3nasb9d( b .5 cm thick (assume conductivity of air) and area 39yd/b(abnsl$410\,m^2$ 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 og5vjlptv1 csm- :f*1 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 6- vhc4fq kjq/*nppob 93ij e8Problem 58, take into account radiation from the leaf to calculate how much water-c po34j 6pqbj*8 9k/hqnevif 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 enlds0bhab 7 g:3ters the Earth’s atmosphere. If its initial temperatud7h3glbba0s: re 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 Ea dm1k x.vw2,cjrth’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 soft rucigl.pl w,i;2)ozdli gm 33*vbber ball at a wall until they are about to drop due to dehydration and exhaustion. Assume that the ball hits the wal3)lmzcl, p g;.ig2wi*od 3 lvil 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 finalfj5q(js:0v9 o9b iiam result when equal masses of ice at 0$^{\circ} C$ and steam at 100$^{\circ}C $ are mixed together?

  In a cold environment, a person can e0+ w dyw.2kjs0 ps7bslose heat by conduction and radiation at a rate of about 200 W. Estimate how long it0y 0jpsbs 2k.+7ds wwe 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 9 (tf-uj)omev dishwashing, there is “no hot water” left in the 50-gal (185-L) water heater. This suggests that the tank has euto( f)9 e-jmvmptied and refilled with water at roughly 10$^{\circ} C$. (a) How much energy does it take to reheat the water to 50$^{\circ} C$? (b) How long would it take if the heater output is 9500 W?    s

  The temperature of the glass surface of a 60-W lightbulb is 6u7xov9mtb(yx,l j,e*/)wzkhay.8 l g 5$^{\circ} C$ 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.    $^{\circ} C$