What happens to the work done when a jar of oranly9mtxx.x8xa v1 ga1dfd,m9aki(3 m 9ge juice is vigorously shaken?

When a hot object warms a cooler object, does temperature flow bze2d)n/hv,- fc rjn7q etween them? Arefhe -/ n,)7jdq2 nvzrc the temperature changes of the two objects equal?

(a) If two objects of different temperatures are placed i3as 9*j;n1sc gu6hwlo n 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 e6c31jg*aos9 n hsuw l;ven if the internal energies of the two objects are the same? Explain.

In warm regions where tropical plants grow but the 5pux oe/o*pz)7yrm6 bie z(v 3temperature may drop below freezipipr 7*3/ x)om yb6v u(5oezzeng a few times in the winter, the destruction of sensitive plants due to freezing can be reduced by watering them in the evening. Explain.

The specific heat of water is quite large. Explain why this fact makes wti hasjc i1 h:81zzt eqo1+q1b.,rfp( ater particularly good for heating systems (that is, hofo1 jqp+,q8.tizsa1hh e ti1cr :zb(1t-water radiators).

Why does water in a metal canteen stay cooler if the nbey(kn1+-8boptdyx+ quh ); cloth jacket surrounding the cant++bpn eu)t1b;nhdk xy-q y 8(oeen is kept moist?

Explain why burns caused by steam on the skin are often more severe than burns cp;uxj) xlam8; aused by watej)px8mu alx;; r at 100 $^{\circ} C$ .

Explain why water cools (it 03s0a ev;aorz+n . zr1) cp6tumspt)es temperature drops) when it evaporates, using the con 0s )61emo z3+.rtpepva 0n)a uszrc;tcepts of latent heat and internal energy.

Will potatoes cook faster if t7 sw99yn(h ymihe water is boiling faster?

Does an ordinary electric fan cool thb7gzo0dlz * gc*.z8h2 cp hb(oe air? Why or why not? If not, why use it?

Very high in the Earth’s atmosphere, the temperature clav8l d+d+y31kp xk .-lvbsi;an be 700 $^{\circ} C$ . Yet an animal there would freeze to death rather than roast. Explain.

Explorers on failed Arctip:v5u x w 6lgcxe/9iw:,vdyoq ;h24um c expeditions have survived by covering themselves with snow. Whye9vi 456yo, l/ xmc h2qpw:v ;xuuwg:d would they do that?

Why is wet sand at the beach cooler to walk on than drya5z0fs iafu,0 sand?

If you hear that an object has “high heat content,”rc55 cn73 dfn.b*l m)r epam7n does that mean that its temperature is high? Explain.*cafcm5r537bprn)7 n dl me n.

When hot-air furnaces are used to heat a house, why is it important thafaw(1fk.7+qgrbamgen:a 4jt 5 pr,+it there be a vent f bg4 aaj rp +krt e,wfqf:(+5imgn17.aor air to return to the furnace? What happens if this vent is blocked by a bookcase?

Ceiling fans are sometimes reversible, so that they dri iwcx;to 3:1 ubjb 0),j vvqak8dy3f7yve the air down in one season a u)jt ;b83x3,7bd0yq1:jky vwic ov fand pull it up in another season. Which way should you set the fan for summer? For winter?

Down sleeping bags and parkas are often spaim75: ujs2qaecified as so many inches or centimeters of loft, the actual aau:isq5mj27 thickness of the garment when it is fluffed up. Explain.

Microprocessor chips have a “h3keye-e.ig*s 4 h20nukjf-yxq;0 nr ceat sink” glued on top that looks like a series of fins. Why is it shap; 0 kig0.2ej34k-x eq-cerhus nf*yyned like that?

Sea breezes are often encountered on sunny days at the shore of a large body 5b:fxcdl fu54+*p m9p)6oqd+pbj qp4w pl7xpof water. Expxc5 *f5 : df)lpb+pm6p7pw 4d+quxjpl49 p bqolain in light 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 dkh5,k 5j4lpjb /ucgpjiz0 -5the air can flow is often cooler than a floor that rests d50,-pk/ 4hj di pbjk55z ljcugirectly 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 readine/3ue cnxa) ;egs are always taken with the thermometer in th;a 3xnc/eee )ue shade.

A premature baby in an incubatorz x 8(v1i:mmseeh6vrd+*y.hq can be dangerously cooled even when the air temperature in the incubator is warm. Explair6. sh: +hxmz vye *ieq81dm(vn.

Why is the liner of a thermos bottle silvered (Fig. 14–15), and why does rnqzit,crm)./t 2p o.vqg0:eit have a vacuur , i0)/z2 mtnpc.oqgtrvqe:.m between its two walls?

Imagine you have a wall thr8x97 u/ia)qh r gm;lc//e hz kb,w6yfat is very well insulated — it has a very high thermal resistance,zfy/a crbhh/l6ger);w iuxk ,8q97m/ $R_1$ 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) venti d4//xq;vnum h .*e(wf,euim3yseef0lation 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 reduce which of these heat losses? Explain in demd(/q*eym0h wv 3 e,4 x feues.un;f/itail.

A piece of wood lying in the Sun absor3pi2vui* (m ufbs more heat than a piece of shiny metal. Yet the woodi2p uum(v3*fi 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 tha n(yar+n9ol /1hdl )qon when cloudy1/nhyll9)qn(o a d +ro. Why?

An “emergency blanket” is a thin shiny (metal coated) plastic 35 /s3oi8,pwhtw*c iagp pbi4foil. Explain how it can help to keep an immobip3iig is8o453 b/tap*, wp hwcle person warm.

Explain why cities situated by the ocean tend tckrpi51b4n +2bg dg2zp8z- gwo have less extreme temperatures than inland ckg14gn5z w-pi gdb 22b8r cpz+ities at the same latitude.

  How much heat (in joules) is required to raise the temperature of 30.0 kgo,b:qfux*e yj;z qb27 of water frfo2qjzu;b,:b7yq *ex om 15 $^{\circ} C$ to 95 $^{\circ} C$ ?    $ \times10^{7 }\,J$

  To what temperature will 770. :o ilbn8f8z 77vqa )uqoann80 J of heat raise 3.0 kg of water that is initially at aq8qo .nn8v7n7l uaz8bof i:) 10.0 $^{\circ} C$ ?    $^{\circ} C$

  An average active person cot ykn o, /bhm197h ifx7.v9psynsumes 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 of uniq /buik+v;cm;9s a3 khts. One Btu is defined as the heat needed to raise 1 lb of water by 1 F ;+s/vamh9q k 3kbu;c i$^{\circ} $ . Show that
1Btu = 0.252kcal=1055J

  A water heater can genera wwmjdi6 p1 uz4t-z)e*te $32,000\,kJ/h$ How much water can it heat from 15 $^{\circ} C$ to 50 $^{\circ} C$ per hour?    kg/h

  A small immersion heater is r(vuxi -fl. pz7ated at 350 W. Estimate how long it will take to heat afi z .(vuxp-l7 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*yn9u xf1njb * brakes are used to bring a 1200-kg car to rebnx*1*f9nuy jst from a speed of $95\,km/h$ ?    kcal

  An automobile cooling system holds 1/qrgtm6stb5 )d-k d 0v6 L of water. How much heat does it absorb if its temperature rises fro50kdb-r6tdv)m gq/ts m 20$^{\circ}C $ to 90$^{\circ} C$?    $ \times10^{ 6}\,J$

  What is the specific heat of a metal substance if7-t l +gt,vsg(ro)gqiap:d s( 135 kJ of heat is needed to raise, ig dqg7(a( stv+gr )l:o-stp 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 water experience the same tempv y 5(smihk6w8erature rise when they absorb the same amount of heat. What is h( 8sw5 vk6yimthe ratio of their masses? [Hint: See Table 14–1.]$m_{Cu}$ : $m_{Al}$ : $m_{H_2O}$ =    :    :   

  A 35-g glass thermometer0lx1 mn vm4ly) reads 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-gd*4 iqr,. ,actx2if wn 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 horseshoewsdk/ns7auf)9d1 6p c (mass = $0.4\,kg$) 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 je6)2up h5b 6s *ns5 ( fbhpzr6fiqzx1is 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 blhj.;g 8nmdm9oil 0.75 L of water initially at 8. g9;.h8lm jmdn0$^{\circ}C$? 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 conx lga ,p/n09udtent of 75 g of candy from the following measurements. A 15-g sample of the candy is allowed to dry before putting it in a bomb calorimeter. The aluminum bomb has a mass of 0.725 kg and is placed in 2.00 kg of waterpd lna/9gu,x0 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 180*a w sb-bysp,*(1cfko $^{\circ} C$ 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 6 pvkb4lraw-),l1u3dhu 6o ngipf:+xof $6.5\,m/s$ 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 obj u-uksd0p/d70mma( cuect is defined as the amount of heat needed to raise its tempcus(kmm 0pu -d0au 7/derature 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 in0.st.va36hn4duw kb yitially at 20$^{\circ} C$?    $ \times10^{6 }\,J$

  A 0.095-kg aluminium sphere ghsd /*r) bm7 )cfq8hbd ebh89is 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 is its temperaturedfg )h 8q7bmb9erhchds/b* 8) increase?    $C^{\circ}$

  During exercise, a person may give off 180 kcal of heat ik+*mip4j y z+6j;tidw kt /a/xn 30 min by evaporation of water from the skin. How much waterk yd+;awi+mp64x tzj*/t/ki j has been lost?    kg

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

  A 30-g ice cube at its melting point is dropped into an insul3hz2a2z59jg9et z+3eoex gn oated container of liquid nitrogen. How much nitrogenn9gz39zh3x ao2 2 joet5 z+ege evaporates if it is at its boiling point of 77 K and has a latent heat of vaporization of $200\,kJ/kg$ Assume for simplicity that the specific heat of ice is a constant and is equal to its value near its melting point.    kg

  A cube of ice is taken from tyvt sipvd30: 0he 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 water atq61y+2 grxfhdn k*6zu 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 span of fou33x tf4 f5j5nd ifbgma c+y*)/m dlk6vr hours. Making the approximation that all of the cyclist’s energynla/div )y4bx3+kfcf5f mdm 5 j*tg63 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 100f/ qw8vzsf; cvc 4c1;udhd9u,$^{\circ} C$ 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 isa2 zi yg50jpuv.c s.k8 $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 fq *+:t 0ginz.ps4rdxat $250\,m/s$ 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-skatera o6d : yfrvrhu t(t2oxyp7*51 moving 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 investigator notes that the 8.2-g lead bullet th, n-8:u punq: y iu7pkswh)a.pat was stopped in a doorframe apparently melted completely on impact. As,p-nws k:u: . )8pu 7paquinyhsuming 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 rox7d;g +p (cecfap 5 0oigrx57vd 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 cg;iqirt 0*.swd +),ltt nitl+onduction in Example 14–10, assuming that there are strong gusty winds and +.itl) ig rw*t q+,idst;0nt lthe external temperature is -5$^{\circ} C$   $ \times10^{4 }$ W

  (a) How much power is radiated by a tungstut s0lf36wq ut ,o:z*2jonvcb6l 06ljen 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 conduction from the bf wo. *l,rnu.flood capillaries beneorfnl. w*., fuath 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-thickutkp-2+ rq(e4kzko4be8q mw4 brick wall. Because of a numbkzm +u( kr eoq82t4ebp4-qw4 ker 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 to melt a block +4tmwum m:(yb* ,)biati q3w aof ice at 0$^{\circ} C$ with a flat horizontal area $1.0\,m^2$ and thickness 1.0 cm? Assume that the Sun’s rays make an angle of 30$^{\circ} $ with the vertical and that the emissivity of ice is 0.050.    h

  A copper rod and an aluminum rod of the same length and cross-se/30w 2q wxstnwctional area are attached end to end (Fig. 14–18). The copper end is placed in a furnace maintainedxt/3 q wswn2w0 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 which the whole Earth receiv+ ph kmo w5m4- bdze.dln(: lx0g5vz+hes energ vbwhxz 4+l(hlm- :z0eodd+p5 m.5nkgy 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 dissipat.gv stun (e)-aed through a glass bulb thatvge-a )u(. stn 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 the glass?   $^{\circ}C $

  Suppose the insulating qualitq*3a0 lwmoa (zies 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 total area ismlo(awzq 30*a $240ft^2$ and the temperature difference across it is 12 $F^{\circ} $?    Btu/h

A double-glazed window has twcpw )- 8 .sem*gixcauw6nh 5 z(h(.sefo panes of glass separated by an air space, Fig. 14–20. (a) Show that the xcgcpzemf(u() a i*hwsseh56n -..w8 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 1;e;d3jjbno . s:vec*k 1.0 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 o p* 9.xz7j0emr-f md;)wqb nftf 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 ocr7xp)nufsp q:ph :6- z09he neeans, estimate the heat liberated when a cube of ocean water, 1 km on each side, is cooled by 1 K. (Approximate the oc90p:qxs nphe ef zh-np) ru67:ean water as pure water for this estimate.)    $ \times10^{ 15}\,J$

  A 15-g lead bullet is tes) qecn*4x5 j5g tf84qe hg3ggsted by 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 system has a temperature rise measured as s8q egx)fg4 et5gngh* 5 j3q4c0.020 $C^{\circ} $. Estimate the entering speed of the bullet.    m/s

  (a) Find the total power radiated into space by the Sun, assumingax.f ivo5g0c0- z3 zq1f qtin( 7)plb7naylo0 it to be a perfect1nnf - 37a )cipblx7 fiqt.gy50o0 vl(z0o zaq emitter 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 p* w6axa(mq0j kcb .ad5erson 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 falls a vvo5d .g08 gxfclmch88ertical height of 140 m before striking the ground. Estimate the temperature rise of the rock if 50% of thgcoc8dv fh.l5x g08m8 e heat generated remains in the rock.    $C^{\circ} $

  A 2.3-kg lead ball is dropped into a 2.5 c/fx lxvh0-5q-L insulated pail of water initially at cq5-l x0h vf/x20.0$^{\circ} C$. 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 1j ttg m26xi1f2c z-aqcm thick with total surface aregt2a1xz f ij1cqm62-t a $1.2\,m^2$ 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 hajq 5rge ajg9j362hyc8 s an 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 heloli:w6+8 5gl(nhhaegh,1 ue at can be conducted from the interior of the body to the ,68u5i+g n1al(ege lh :hhlwo surface. Assume 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 wq. sbxr 1uu/r( 5bv+/ 1yijgumalls 17.5 cm thick (assume conductivity of air) and a+guy usb rmb /5/1q.i(urv1xjrea $410\,m^2$ 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 travel . ldhp)kprdbww-a(( ; o42lfsing 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 from vsy x5,j9 *wobb(h (ththe leaf to calculate how much water must bt,hjbs 9o(y w(hx* 5vbe transpired (evaporated) by the leaf per hour to maintain a temperature of 35$^{\circ} C$.    g/h

  An iron meteorite melts when it enters the Earth’s atmosphere. If its initial txd 7f/**cvy akemperaturf7dcx**y/ v kae 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 cruwsnf1v k 8,z46jup5 hist 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 2xx bf e7x(yee3d/,8 gap:ymdpeople hit a soft rubber ball at a wall until they are about to dropm2dey:3gx/xbda8fey( 7 pxe , 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 equal.(w7d:oiu6 -kgjd p lg masses of ice at 0$^{\circ} C$ and steam at 100$^{\circ}C $ are mixed together?

  In a cold environment, a person can lose hea rjfg8 s;:0 dohbez-v0t/1pz wt by conduction and radiation at a rate of about 200 W. Estimate how long it would take for the body temperature to drop:vwr1o j8sdtf 0pgz/bzeh-;0 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 in th 1v)bzfevui-fwe. 93e e 50-gal (185-L) watue9zevfb1fwe i. v3)-er heater. 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 60-W ligh(hjm:dv, hjxq oq,48yw 5;bmptbulb 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.    $^{\circ} C$