What happens to the wore i ilnl)3ke1ucx)22bk done when a jar of orange juice is vigorously shaken?

When a hot object warms a cooler object, qd m6pz9/sgnivvy9 2o9-- v3 askfi-fdoes temperature flow between them? Are the temperature changes of the two objects equal?2-m-6vvp-fdgz /9isq kyaivn3o 99 fs

(a) If two objects of different temperatures are placed in contact, will heap icjnymp 0c x4nm1q))r x4r(/t naturally flow from the object with higher incc ynp4(xinm10r 4j))q/prmx ternal energy to the object 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 rjzt(dy*a() j the temperature may drop below freezing a few times in the winter, the destruction of sensitive plants due to freezing cyra(* )d (jjztan be reduced by watering them in the evening. Explain.

The specific heat of water is quite large.4f+ au2qwjb ; 7y4aman Explain why this fact makes water particularly good for heatingaj7mya+2 f 4 nq;b4auw systems (that is, hot-water radiators).

Why does water in a metal canteen stay cooler if the cloth jacket surroundint iw8ap-mhn+,.rn tl/ g the canteen i+l.wpathi , r/8-mn tns kept moist?

Explain why burns caused by steam on the skin are often more severywbm,;. p(pvze than burns caused by water v; b,pywm.( zpat 100 $^{\circ} C$ .

Explain why water cools (its temperature drops) wamlye6 (qbv/lgc hyj9w:,/-qhen it evaporates, using the concepts of latent heat aq9jh/lb-v w:,(gmqla e6yyc / nd internal energy.

Will potatoes cook faster if the water is boiling fas4 5ll-vgwo+tl8b *jqwter?

Does an ordinary electric fan cool the air? Why or why no,)wko7 x8 aw*ltu92y+k mvdpyt? If not, why use it?

Very high in the Earth’s atmosphere, the temperature canaxh:1b**t k3 )/dzq ua wmszv6 be 700 $^{\circ} C$ . Yet an animal there would freeze to death rather than roast. Explain.

Explorers on failed Arctic expeditions have aig yddw a5w43(l.(z nqcm-h7survived by covering themselves with snow. Why would they do thw4(dc( a-.hwimya dql7g3 nz 5at?

Why is wet sand at the bez;tw qrs*0s*vach cooler to walk on than dry sand?

If you hear that an object has “high he xx 2c,s 9x-qn925nwjowzj(uqat content,” does that mean that its temperature is high? Explnnq su-zj2 jwcx29wq,9x5x o(ain.

When hot-air furnaces are used to heat a house, why is it imjzmu5 3m op9)nox* e*s fr;-uvportant that there be a vent for air to return to the furnace? mu- 3)opu f * o*5xnmejzsv9r;What happens if this vent is blocked by a bookcase?

Ceiling fans are sometimes reversible, so that they drh(c 2n6f tg eksl icj69nrm:6+ive the air down in one season and pull it up in another season. Which way should you set the fan for summer? For w gn+lkr :mj66i es6ccf9(2nth inter?

Down sleeping bags and pl1h)zb4tr xv4d4 ,blr arkas are often specified as so many inches or centimeters of loft, the actual thickness of the garment when it is fluffed up. Expl)dl1hl, 4 4 rxzbvbt4rain.

Microprocessor chips have a “heat sink” glued on top that looks 5di sp+yvq7b.o p +n1ylike a series of fipv +sy o b+q.ipd5n1y7ns. Why is it shaped like that?

Sea breezes are often encountered on sunny days at the shore of a8: vug,oth ,txy b*ju si.a aheg31.g3 large body of water. Explain in light of the fact that the temperature of theb3u ihe t*,sxgvth ..ag:,aogj31uy8 land rises more rapidly than that of the nearby water.

The floor of a house ome2cnp 7z v++6w1o eqgn a foundation under which the air can flow is often cooler than a floor that rests directly on the ground (such as a concrete slab+wgzn o q+1 6m2cpe7ve 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 taken with the thermometer in.jt 4k0zs:.ag 7sue pt the shaz. p40.uj: 7tseagsktde.

A premature baby in an incubator can bewdrk 50gpd*y2 dangerously cooled even when the air temperature in the incubato w5d0pryd2* kgr is warm. Explain.

Why is the liner of a thermos bottlh54 5igo7bgw 4e8r5p)r(o nxb w+d. day2ijpl e silvered (Fig. 14–15), and why does it have a vacuum betweerbg.gw5+ l a5o edi7oh8w 4y5j)i( rxd4p2bnp n its two walls?

Imagine you have a wall that is very well insulated — it has a very h,*bo( kjg s*/wprfw9e igh thermal resistance je/9,*wb pgs(k*f rwo, $R_1$ 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 fol,lmf1xa 8;x2yaf8v gllowing processes: (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) thevfy;al gaml88x,12xf 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 /(d5g* uzq vzk dkv,m0piece of shiny metal. Yet the wood feels lz,d(gv/vzk d0 qk*mu 5ess 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(6xdi2;fs8wx fwgb :an whefx;xaw 2 (df8w6 sgi:bn cloudy. Why?

An “emergency blanket” is a thin 9 pa0flavpg.1q wmk+ eu4tcz7+6 i)vq shiny (metal coated) plastic foil. Explain how 4u0a qe1mgqt av6 lv w7.i9pp)czk++fit can help to keep an immobile person warm.

Explain why cities situated by the ocean tend to have less exensd 2r*3qq a+treme temperatures than inland cities at the same latitude q+*3raqd2 nes.

  How much heat (in joules) is required to ra2 bi;y9qt fu8:oc-hhfise the temperature of 30.0 kg of wat:8bc;fq tio -2yuh9 hfer from 15 $^{\circ} C$ to 95 $^{\circ} C$ ?    $ \times10^{7 }\,J$

  To what temperature willu5lyvj g(gbvg2 8hcm1o- ( x+l 7700 J of heat raise 3.0 kg of water that is initially at l5 -hx1c+ l gvm8v u2ggyjb(o(10.0 $^{\circ} C$ ?    $^{\circ} C$

  An average active person consumes about 2500 u9t 1exoc,0q dy*o2 j5fjps6 g/lgch(y ;(wspCal 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 l(fj7nvv dz-+pb l7t5(Btu) is a unit of heat in the British system of units. One Btu is defined as tl7vpzf (vd+7j -t lb5nhe heat needed to raise 1 lb of water by 1 F $^{\circ} $ . Show that
1Btu = 0.252kcal=1055J

  A water heater can generate o *yy:x7ai.opq.tj:*e6x41 c vwy gnt $32,000\,kJ/h$ 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. Estimat. 0ssr 5/qkic u4p)nrfe how long it will take to heat a cup of soup (assume thsk4/0rur. i pf)nqc5 sis is 250 mL of water) from 20$^{\circ} C$ to 60$^{\circ} C$ .    min

  How many kilocalories are generated when the brakes are used to bring a 1200q5b6jcbm7 31y1gu te,z.ztq v-kg car to rest from a speed ofy t eb m1cj5v,ztqgqb31u z6.7 $95\,km/h$ ?    kcal

  An automobile cooling system holds 16 L of water. k hei *k/dbc )z/ )q.dcver;3dHow much heat does it absorb if its tempe.;ec di cz*kdq/b rd/e h)3v)krature 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 isetu 685hbiymv**sl m* needed to raise 5.1 kg of the metal from m5s lvemtyhb**68 *iu18.0$^{\circ}C $ to 31.5$^{\circ} C$ ?    $J/kg\cdot\,C^{\circ} $

  Samples of copper, aluminum, and water experience the same tempdd /w ce/:b):gp 0vl3d7h hucrerature rise when they absorb the same amount of heat. Whcudrhb) :c37/hld /:e0pwg dvat is the ratio of their masses? [Hint: See Table 14–1.]$m_{Cu}$ : $m_{Al}$ : $m_{H_2O}$ =    :    :   

  A 35-g glass thermometer reads 21f8k6ilmnas rt**)cou ei* +sr/va0 0s +g ye4e.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 bl l+jn zd.z7pd7: yxox(ock 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 6aor18b zmw .abp;f.jz.k v)m (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 isnporjry 3yd3v;84d s3 heated to 330$^{\circ} C$ and then plunged into a 105-g aluminum calorimeter cup containing 165 g of water and a 17-g glass thermometer at 12.5$^{\circ} C$ . The final temperature is 35.0$^{\circ} C$ . What is the specific heat of the substance? (Assume no water boils away.)    $J/kg \cdot C^{\circ} $

  How long does it take a 750-W coffeepot to bring to a boil 0.75 L of water initi dw +wza,g p6;6bk .gr2caqbr,bd +crb wa,k.;waz, ggqrp662ally 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 o ygxrx8 bhn o2szv;()/f candy from the following measurements. A 15-g sample of the candy is allowed toz;)nx/b2 8hxog(syv r 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 iron at 18rru jzbv7ljlmx. ,:9afqxkq;y(819 u0$^{\circ} C$ 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 akp1 q;j+:* y7un dt7ba+br sce 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, ofnvenbm,p.1/6e o. g;m3cw vcgccu9 g1d sb x/7 an object is defined as the amount of heat needed to raise its temperature ;bs/bc9ev,61g1pg3 g/. mu dcnv mcx7cn o.we 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 isod29 hzt2.q4x gmxey; initially at 20$^{\circ} C$?    $ \times10^{6 }\,J$

  A 0.095-kg aluminium spfo)gql4ud)u7 w; gpcn.)amb/ here 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 7mgwbpauu)fd ;qco. )4ln)/g sphere, what is its temperature increase?    $C^{\circ}$

  During exercise, a person may give off 180 kcal of heat in 30 b3q4o vhf m/z(min by evaporationzvoh( 4m fqb/3 of water from the skin. 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 its melting point is dropped intoo3zpy)-v hwd jr6l-: kyf7-ms an insulated container of liquid nitrogen. How much nitrogen evaporates ifrf6dy:s 3l-)ywhv -7-mokpz j 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 fromgh1/y tfb +o(sf ;-owu- cjd6r9o3 bhu the freezer at -8.5 $^{\circ} C$ and placed in a 95-g aluminum calorimeter filled with 310 g of water at room temperature of 20.0$^{\circ} C$. The final situation is observed to be all water at 17.0$^{\circ} C$. What was the mass of the ice cube?    $ \times10^{-3 }$ kg

  An iron boiler of mass 230 kg contains 830 knrd/xs; ae7+ltfjp0 :g of water at 18$^{\circ} C$. A heater supplies energy at the rate of $52,000\,kJ/h$ How long does it take for the water
(a) to reach the boiling point,$\approx$    h (Round to one decimal place)
(b) to all have changed to steam?$\approx$    h (Round to the nearest integer)

  In a hot day’s race, a bicyclist consumes 8.0 L of water over the span of foui.un,r hp ;j:xr hours. Making the approximation that all of the cyclist’s energy goes into evaporating this water as sweat, how much energy in kcal did the rider use during the ride? (Since the efficu.rnij x,; :hpiency 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 1st:n;y )uj2o( p9eue9l i3xmm00$^{\circ} C$ 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 me8i qor)(9)w3rr6 azjsvpm h: urcury 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 travelhjm(;wk sv4x (ing at $250\,m/s$ penetrates a block of ice at 0$^{\circ} C$ and comes to rest within the ice. Assuming that the temperature of the bullet doesn’t change appreciably, how much ice is melted as a result of the collision?   g

  A 54.0-kg ice-skater movbxgo on v*eohk11h).ob/f,ha3 p, 7ohing 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 bulletd((t8pl)9i lhia o f*u that was stopped in a doorframe apparently melted co9atd ihpf)((u8o *l ilmpletely 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 alum ukwgr o:6nt;8inum 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 conduction in Example 14–10,v v; 7m5 wjrwrh0oeatwvp3/ /n2-mf1u assuming that thr/ 3re/npomjvv50a mt2;ww fvw71uh-ere are strong gusty winds and the external temperature is -5$^{\circ} C$   $ \times10^{4 }$ W

  (a) How much power is radiated by ax7s;jg37yw/ppjp7 f o 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 skizjoyms e9+ 7 jj 3dl(epw(rt64zyr0z/n. Suppose 200 W of heat flows by conduction from the blood capillaries beneath t +rd(ojspwye(jz 70jmz4 y/l69e rtz3he 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 brick ho xma.,n2,s)s+v :7tnd*m*vj gqc uewall. Because of a number of 100-W lightbulbs in one room, tnom7,jdstu *e, m+vcvnaq:*hs ).2gxhe 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 blockv hvqg(pgeco*u4 - b(a7+vu1et: cre6 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 length and4 o+s7kvmgoocex9*b7 cross-sectional area are attached end to end (Fig. 14–18). The copper end is placed in a furnace maintainedo9k4sevmbo7+*c7o gx 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 wholen;8f neqfgr 9bupj0y9fu 7+sshl e+.; Earth receives energy from the Sun. hen7fsr8jy fe; b09f s +ugul9n p;.+q    $ \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 ax*:yix(88r +yoiy dwc.nb iy:9ixo1 a glass bulb that has a radius of 3.0 cm and is 1.0 mm thick. What is the difference in temperar(8*oy 9:o1yic na ixx:iwy. yibdx8+ture between the inner and outer surfaces of the glass?   $^{\circ}C $

  Suppose the insulating qualities of the wall oemre o 5m 28 7baw-z(pm.yh;eef 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. Whapoa-; yme(5 7be2em8z ehrwm.t 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 pangj /xqqk;c *7v hq)le3es of glass separated by an air space, Fig. 14–20. (a) Show that the rate of heat flow t /qqjxhel cg*7)3;vqkhrough 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 at nxlcz7+k0- u k+5b hpd0$^{\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 zh(4gyat e**yliquid 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 oceans,2,rqwtl ypi:8jkf 0 )c estimate the heat liberated when a cube of ocean water, 1 km on each side, is cooled by 1 K. (Approximate the ocean water a plfqwcr,tj:kyi 80 )2s pure water for this estimate.)    $ \times10^{ 15}\,J$

  A 15-g lead bullet is tested by firing it into a fixed block of wood w fkb.j0 tv- 8ra;o7m7f0 praftith a mass of 1.05 kg.07m -. fpb0kf at8of; a7rrvtj 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 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+0z 9jelmxhgty :3k i8 be a perfectmk803x:g tjiy +h l9ze 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-kgoxpct t3myd fc x(3l8(o8xar7- u1cb: 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 57t(as 5x) redon 9jsxcliff and falls a vertical height of 140 m before striking the ground. Estimate the temperature rise of the rock if 50tsxxs55 n ar(97 )jdoe% of the heat generated remains in the rock.    $C^{\circ} $

  A 2.3-kg lead ball ish-nvq *p;ozj 48fxn aer4ijr,9kf+ob5 l.4 ao dropped into a 2.5-L insulated pail of water initially at 20- n.8fx4eon 5fjka+aoz 9hr ,44 pr bqv*l;joi.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 cm (vo ,k g.bc8czthick with total surface are kz ,cv.g(bc8oa $1.2\,m^2$ 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 metad jj.s.+yuax68dhrf/d8p j.cbolism 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 interior of*o zv 5r4t7z2ld4g7rcrayaw + the body to the surface. A4 5+lz *7zac g2w7orda4vrr ytssume 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 17.5 cm thic1vfu ,-oqpp14 mwyab6k (assume conductivity of air) and 6a vqwbm,u41ypp-1f oarea $410\,m^2$ 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 travisdw+ h2 nvy;3eling 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, sqtcq;2yj *e, take into account radiation from the leaf to calculate how ;c2*qjt qs, yemuch water must be transpired (evaporated) by the leaf per hour to maintain a temperature of 35$^{\circ} C$.    g/h

  An iron meteorite melts when 0fjalm* b4g3a it enters the Earth’s atmosphere. If its initial temper0 *3gbja4amf lature 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 +06xmiil ktzu9 c/1qk 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 ho 17hu - tirtz:(j5kncit a soft rubber ball at a wall 7 chn(r5u-it zok:1tjuntil 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 equal skz l6v9 6-,vmx4tp.ux qo bq1masses 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 at a uy5xol: - ezxb.lq)r0kc35 ixrate of about 200 W. Estimate how long it would take for thx)quoce.5x l- 0x 35:bzilk yre 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 dishwashi.w 1n5tny vcy4ng, there is “no hot water” left in the 50-gal (185-L) water heater. Thi4c yyn. v5wt1ns 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 glas) 5 cqqf ljrpqdbyr-;agbrm :s5b5 442s surface of a 60-W lightbulb is 65$^{\circ} C$ when the room temperature is 18$^{\circ} $C. Estimate the temperature of a 150-W lightbulb with a glass bulb the same size. Consider only radiation, and assume that 90% of the energy is emitted as heat.    $^{\circ} C$