What happens to the work done when a jar of orange juice is vigorousl *)mk*k f, flf5mg qk/cc6c)kay shaken?

When a hot object warms a cooler objemz 2nn0-lc.p )8*lg ;btzxvkj5a*m zk x(-zpzct, does temperature flow between them? Are the temperature changes of the two objeczx b0l;g2al*mkczvx zz t-mj k)*5znnp-( 8p.ts equal?

(a) If two objects of different temperatures are placed in contah,ky-fw40ds x dbf2e c;iul6:ct, will heat naturally flow from the object with higher internal energy to the object with lowedef y f h;c:l0xw,k -sb26i4dur 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 f1.t-x2/ v +fgj(lrs hntbl w5but the temperature may drop below freezing a few times in the winter, the destruction of sensi/gsvh f5lf+ t-nx (j2r tw1.bltive 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 mavdg 4kn7iwi2.jf+qsy (9 2,yyi ;dwbrkes water particularly good for heating systems +;,7jq. dyrwgndyfiy4iv2wk i2s(b 9 (that is, hot-water radiators).

Why does water in a metal canteen stay cooler if the cloi 6 mimy( o36z na-4x q*ctdalg;)qx3ith jacket surrounding the canxi;6a) i noqgm6qlticd -x maz34*( y3teen is kept moist?

Explain why burns caused by steam on the skin are ofbhefl o.c-,zrg8-o4x jt:qc( ten more severe than burns caused by watlf4:-ghtr c( ,xo8q.ojc z-eber at 100 $^{\circ} C$ .

Explain why water cools (its temperature drops) when it e+sv -tj.thgsa 4u7(qkvaporates, using the concepts of latentksqg-.a+u 7h t4 vs(jt heat and internal energy.

Will potatoes cook faster if the water is boiling faste -gy,;w-q d ho,qf*krwr?

Does an ordinary electric fan cxx yhkxy1 fk y77 *ou+v+g-po/ool the air? Why or why not? If not, why use it?

Very high in the Earth’s atmosphere, the temperature can be 43 klr w1e2dvv700 $^{\circ} C$ . Yet an animal there would freeze to death rather than roast. Explain.

Explorers on failed Arctic expeditions have survived by coverinvu lthi; m2bmu,sh 744g themselves with snow. Why would they do m7,hs lbhti;uv4 42m uthat?

Why is wet sand at the beach cooler to walk on td r joe*two .6)skm -:pt)jhm;han dry sand?

If you hear that an object has “high heat content,” does that mean that p2 q3 vw)d(psmits temperature is high? w) v (3spdmp2qExplain.

When hot-air furnaces are used to rpilhys2pv: tjgi*7-4+h.v c heat a house, why is it important that there be a vent for air to return to the furnace? What happens if this vent is blocked bg rsjh4ctiv.yp :p2*7i l hv+-y a bookcase?

Ceiling fans are sometimes reversible, so that they drive the air drq;cgb6; kr3k:b*b w 7 my5zayown in one sea5r kg*r7;bk 3y ; 6mc:byazwqbson and pull it up in another season. Which way should you set the fan for summer? For winter?

Down sleeping bags and parkas are often specifih,w3axx hws;q -;kmb pth,w59ed as so many inches or centimeters of loft, the actual asx-btk h,,5 ww9h3wm;hx;pq thickness of the garment when it is fluffed up. Explain.

Microprocessor chips have a “heat sink” glued on a2v6nwp ;bbe -m:.l3wxab;zatop that looks like a series of fins. Wv: ba 6na.2we;a 3;b wxlpm-zbhy is it shaped like that?

Sea breezes are often encountered on sunny days at the shore of a large body ogd z 1*yfpfse *)9-rpk+e 1dznf water. Exp 1+dp*k py- d1egs f9zz*rnfe)lain 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 the air canm oaj6(j ,n4o39s*txzxbctc/ flow is often cooler than a flooram9zsj 6c4 n oxo(j*cb3x ,tt/ that rests 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 taken i o iy.b(ks2dg( (f,mfwith the thermometer in thi(g 2fi(d ksy o,.fm(be shade.

A premature baby in an incubator can be dangerously r kd3 65qlyu3x9f;pmv cooled even when the air temperaturv3uk ;pr9xd5lqy 36m fe in the incubator is warm. Explain.

Why is the liner of a thermos bottle silvnpzrm; iz84dg6*0c ha;u+f jz ered (Fig. 14–15), and why does it have a vacuum between its tc; 84zdz igrmzu6pfja* 0; h+nwo walls?

Imagine you have a wall that is very well insulated — it has a ver2uc4s hgl 20iji+3wcqr/kjphr + .xy9y high thermal resistancey2u ik3rx .2qhlgjpr+0hcw9+ / scji4, $R_1$ 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 5 m xvul.7r(7naxa j8aby the following processes: (1) ventilation around edges; (2) through the frame, particularly if it is metal; (3) through the glass panes; and (4) raxa .(ur77mal a5xj v8ndiation. (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 lyingbj4e0d -l7:idv 0 bhdg in the Sun absorbs more heat than a piece of shiny metal. Yet g04:h0l7 vjeiddbbd-the wood feels less hot than the metal when you pick it up. Explain.

The Earth cools off at night much more quickly when tqqf2/kv9z ew1h+ y wz :;9emkrhe weather is clear than when cloudy.vh/2+zkw91;ewk yf: zqqe m 9r Why?

An “emergency blanket” is+.a rn64 z9rky8uwrhc a thin shiny (metal coated) plastic foil. Explain how it 9zkc4.r nra8wh6u yr+can help to keep an immobile person warm.

Explain why cities situated by the ocean tend to have less extreme temperatures .bjv4o. g -uh)ijief7t 4zzy 5than inla.4hyeioi)gvu - jz 7fb t.5zj4nd cities at the same latitude.

  How much heat (in joules) is required 8cugl*p xfz /(to raise the temperature of 30.0 kg of water from *g/l(pfuzcx8 15 $^{\circ} C$ to 95 $^{\circ} C$ ?    $ \times10^{7 }\,J$

  To what temperature will 7700 J of heat raise fqp8s82 frcw r+-ddni 4nht6)rxe4-m u4 ;eul3.0 kg of water that is initially at m c+ -e6uurlr;d f82qwsnx4 h8npdr)t-efi 4410.0 $^{\circ} C$ ?    $^{\circ} C$

  An average active person consumes about 2500 ub fn 3e9-6i2wly0dj2vty)e uCal 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 inc t9z7fcnu4utr 0 9if: the British system of units. One Btu is definet r7tu:z0fu9cni cf94d as the heat needed to raise 1 lb of water by 1 F $^{\circ} $ . Show that
1Btu = 0.252kcal=1055J

  A water heater can gn 2x1gma/(w nj+ 2fg2nk:t q2.lnsocpenerate $32,000\,kJ/h$ 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 W3i:layoc*dg n 6bxp31. Estimate how long it will take to heat a cup of soupdgayl pox:1b63n3 *ci (assume this is 250 mL of water) from 20$^{\circ} C$ to 60$^{\circ} C$ .    min

  How many kilocalories are generated when thf j . gietusl+:ju hbae g:b0(:(8*ikne brakes are used to bring a 1200-kg car to re kei( 8u*a.fesb( itn:ggjhubj 0:l+:st from a speed of $95\,km/h$ ?    kcal

  An automobile cooling system holds 16 L of water. How much heat does it absy*i ryk)+pdd- orb iky*d i)+ ydpr-f its temperature rises from 20$^{\circ}C $ to 90$^{\circ} C$?    $ \times10^{ 6}\,J$

  What is the specific heat of , oi8w w c3ol).bxlxs1a metal substance if 135 kJ of heat is needed to raise 5.1 kg of the mowl8s,c1b3w .xli) x oetal from 18.0$^{\circ}C $ to 31.5$^{\circ} C$ ?    $J/kg\cdot\,C^{\circ} $

  Samples of copper, aluminum, and water experience the sai.7.ov0 /9fq1cmpqopx e n(;7 vtrxhime temperature rise when they absorb the same amount of heat. What;1.7xo/p .eqit(7rfvvhp on9icxm0 q is the ratio of their masses? [Hint: See Table 14–1.]$m_{Cu}$ : $m_{Al}$ : $m_{H_2O}$ =    :    :   

  A 35-g glass thermometer reads 21.6y: ma4s-tw c1 2vtv:jm$^{\circ} C$ 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 kuf c7lf nz8 hgim --,.8xyun-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 (m m-tl,r9bq+x cass = $0.4\,kg$) 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 heat5h4irk, l 8rbaed 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 coffe5iyqdbn)8 0pq epot to bring to a boil 0.75 L of water initially at 8pb50n8 q)q yid.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 ofu6/: pk 1sdtew 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 water contained in an aluminum calorimeter cup of mass 0.624 kg. The initial temperature of the mixture td6/e :ks p1uwis 15.0$^{\circ}C $ , and its temperature after ignition is 53.5$^{\circ} C$ .    Cal

  When a 290-g piece of iron a( yw2s jlzv+f)eaay 89t 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 hammeo +0 6d5xqvcfeog7+d cr 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 am 3saj h*7 dy f-bufmi:zu(ial d-2*d5vount of heat needed to raise its temperature by *5f 7dz3( h*ad:-b vlmi 2ai sduu-fyj1 $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 tsy3qgd; 7 m kot/sm*:bo melt 16.50 kg of silver that is initially at 20$^{\circ} C$?    $ \times10^{6 }\,J$

  A 0.095-kg aluminium sphere incfyla ;0l r 7rvi(i*/s dropped from the roof of a 45-m-high building. If 65% of the thermal energy proinll avi07( c*/rr yf;duced when it hits the ground is absorbed by the sphere, what is its temperature increase?    $C^{\circ}$

  During exercise, a person may give off 180 kcal of heat in 30 min by evaporationxfq 87v1 (onv babe,f( of ,b(v7a1o bxn(f8efqv 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 into an insulated container of l4 :34*v; usp ymfjxs/tgmpecona8- 4 liquid nitrogen. How much nitrogen m / cs8flgo*se 3ua44m:;npp yj vt-x4evaporates 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 freezer at -8.5 r :9xbw:-l hdh2syg))ly gdc0$^{\circ} C$ 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 m p8131frxa7yh7hrbw r, wd3j830 kg 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 -)n cjr1whvy- four hours. Making the approximation that allwyj-)v cnrh1 - 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 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 arg)( c3;x thkxt 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 p7/mkiij hyan* 2l1f2 mercury 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 traveli k hp3le4o+h3gng 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 m pmm.uh*6xz: 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 investigatorzno5( n pcx72 cbm hr f/l+.gz3yfhdyt2;qv 83 notes that the 8.2-g lead bullet that was stopped in a doorframe apparently melted completely on impact. Assuming the bullet was fired at room temperature onhdh7gx.yf c2b ( v rfz5z2t3c/q 38; m+pnyl(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 alumin3y kt( 0ygu u8tfn:n,lum 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 by0 u/rr) /qacnujg01u .auujy+sktv2+ conduction in Example 14–10, assuming that there are strong gusty winds and th)jgvuru1.q+j ucs auut+ 0ka/yn 2/0re external temperature is -5$^{\circ} C$   $ \times10^{4 }$ W

  (a) How much power is radiated by a tungstezqtzq.p-u gbi02z6k);-a i: erukx,sn 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 8;pc-dytp7 :j qj7 i7ph,ppowheat flows by conduction from the blood capillaries beneath th-tj8,7:pwy ippqop7phjc7; d e 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 4.8yal92;i c6rpw ;fkgp 0 m per side, share a 12-cm-thick brick wall. Because of a number of 100-W lightbulbs in one rooi6 ;gywrk f9;pclp82 am, 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 ae2 8l:o/j ibdrd2k0at block of ice at 0$^{\circ} C$ with a flat horizontal area $1.0\,m^2$ and thickness 1.0 cm? Assume that the Sun’s rays make an angle of 30$^{\circ} $ with the vertical and that the emissivity of ice is 0.050.    h

  A copper rod and an aluminum 0ou20tn0srnc rod of the same length and cross-sectional area are attached end to end (Fnn02 0tc0uro sig. 14–18). The copper end is placed in a 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, estimate the rate at which the whole Earth receqso+ cl0k 1p1pives energy from the Sun. 1pkpc1l+qs 0 o    $ \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 a glasmb1se ur29; f5;yyp gss bulb that has a radius of 3.0 cm and is 1.0 mm thick. What is the ; 92p5 ;gyubmse1yfrsdifference in temperature between the inner and outer surfaces of the glass?   $^{\circ}C $

  Suppose the insulating qualities of th,40owiclhyygug ,tcd a x(mx89q0 43ue wall of a house come mainly from a 4.0-in.h4,u3,dtwyg alc 0 408(9xi gqomx ycu 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 separated by an air space,lk/dlllc on)4hpw3y.4 7yh -t Fig. 14–20. (a) Show that the rate of heat flow through such a window by conn-/7h34l4ll y.) tocwdkylhp duction 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 -*wft y c)daf9 ,jvgp5,jpyr +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 liqu8o1u1hjcb*u m3 (xa ieid 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 energyjmtpv:1 2 9upy is contained in the world’s oceans, estimate the heat liberated when a cube of ocean water, 1 km on each side, is cooled by 1 K. (Approximate the ocean water as mv29y:pp1t ujpure water for this estimate.)    $ \times10^{ 15}\,J$

  A 15-g lead bullet is tested by firing it into a fixed block of wood with) xj tuw.c(h1t)+kwgv a mass of 1.05 kg. The block and imbedded bullet together absorb all the heat generated. After thermal eqwtjt1g(u x hw+.kc)v) uilibrium has been reached, the system has a temperature rise measured as 0.020 $C^{\circ} $. Estimate the entering speed of the bullet.    m/s

  (a) Find the total power radiated into space by the Sun, assuming it to be aly 8r+/l la5ap7u,wv p perfect emill5vaw/ar+uly p, p 87tter 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 person may generate ca qs+sv )clf..2duo i/) aa51fzel e7$200kcal/h$ 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 the7(,o smnq-4xkj s:ic s top of a cliff and falls a vertical height of 140 m before striking the ground. Estimate the temperature rise of the rock if 50% of t4os7jn m,kic( x-:sqshe heat generated remains in the rock.    $C^{\circ} $

  A 2.3-kg lead ball is dropped into a 2.5-L insulated pail 796ityuk dq etwtqhg )c ;,-y1of water initially at 20.0q7hwt;, uqk t)detyy- 1g ic69$^{\circ} C$. 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 ad:a+ g;m;gxzn;r vg 6d xt+6me goose down jacket 3.5 cm thick with total surface aregm g6dnt;eda;+gr;:v6+xm zx 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 has an average met.lduryrig tlcb 6(b3ve/ d3 4/abolism 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 ofwlf 4 ry;e0t*f the body to the surface. Asff40r*;l ey wtsume 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 thick ( 6k-kfjm 9; xk vtys2e;mc)ms f4j4s1hassume conductivity of air) and arsv69yxjfc hft sk-2k;)44j mmsm e1k;ea $410\,m^2$ 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 trla4plf.* he8k4 m0 zopaveling 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 r(gdi.s29xfrs ywgd-6n; vd .a adiation from the leaf to calculate how much water must be transpired (evaporated) by the leaf per hour to maintain a temperat( v.dd.-gns9x a;ir2yfgswd6ure of 35$^{\circ} C$.    g/h

  An iron meteorite melts when it enters t+)+.ttrpxc gpl nci*v )z(.iche Earth’s atmosphere. If its initial temv+cptl( +rt.*izc )p.incg)xperature 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 crust increases aboutq/ 2jp24/vnsi3pst(eehe 6qv 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 1bfr4;ey(p rphit a soft rubber ball at a wall until they are about to drop due to dehydration re1b(y;r fpp4and 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 fina6k-) 8ug3q-ndpgkblmy wiz 11l 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 lose heat by conductionb,wc;: zl q0kn f,xuw2 and radiation at a rate of about 200 W. Estimate how long it would take for k0wqwluf x,b; 2n:z c,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” left in95z (ql0b dgzl;co3n :y-tzik the 50-gal (185-L) water heater. This sugz(5 cly-g0okibnz3tz :9dl; qgests 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 60b;246of yhqft- 8w5uvemzdb03f y oj+ -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.    $^{\circ} C$