What happens to the workacbvawk i. hy4fcmf. :*m,v 2, done when a jar of orange juice is vigorously shaken?

When a hot object warms a cooler z937ie q ye yfpoo/6tken,y1 9object, does temperature flow between them? Are the temperature changes of the yy 3e9 o op,1/7iny t96zkfqeetwo objects equal?

(a) If two objects of different temperatures 4s3iseq d/-gw2 c3fhx mk20xaare placed in contact, will heat naturally flow from the object with higher internal energy to the object with lower internal energy? (b) Is it possiblaqxdchmxf0w2gsk i e/2 3-4 3se for heat to flow even if the internal energies of the two objects are the same? Explain.

In warm regions where tropical plants grow urby*gcd tum) d4mv6c 4us6g(.gi :.p but the temperature may drop below freezing a few timgp6v6 iu .mcsgydr4c4(tmd):buu* g. es 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 larlp(yi xa51/a age. Explain why this fact makes water particularly good for heating systems (that is, hot-w x5aly/ai (pa1ater radiators).

Why does water in a metal canteen stay cooler if the cloth jacket surrj2dk (sv*3ez)6 o1icf4hi1 6xdp cjvxounding theoce1dxc26zj1v64 vi kis ph3(f) dx*j canteen is kept moist?

Explain why burns caused by steam on the skin are often mv fmmm+4c ++xxore severe than burns caused by wx+4+vmm+f mxcater at 100 $^{\circ} C$ .

Explain why water cools (its temperature drops) when it evaporates, using the 6-)chjg/ p8xh- y snjaconcepts of latent heat and sg6jnch )yp8--a hjx /internal energy.

Will potatoes cook faster if2 xaiqxr 9 05lbk.uax+ the water is boiling faster?

Does an ordinary electric fan cool the air? Whbk y5hsy1fp- vh0dvk80 -o )iv5t grl4y or why not? If not, why use it?

Very high in the Earth’s atmosphere, the tempera4x1vx8 .s 8 dbfr n*u**cl mvsdat+5akture can be 700 $^{\circ} C$ . Yet an animal there would freeze to death rather than roast. Explain.

Explorers on failed Arctic expeditions have survivckjucx5 - o: );zdw2oammme70ds 0x9wed by covering themselves with snow. Why would they ms5wc7md9o2;0ac-w jk:0 x)xzm odue do that?

Why is wet sand at the beach coolv uq5w1kjrej ql+5-+b er to walk on than dry sand?

If you hear that an object has “h 2cmu(era,1/ptmp- ng igh heat content,” does that mean that its temperature is hig-ra(pt m1p,engc 2um/ h? Explain.

When hot-air furnaces are used to heat a house, why is it impor5-(qmk8yckcwc.j8e8nk pk; ttant that there be a vent for air to rettcyk;pk8c.8km5newk 8 j- cq( urn to the furnace? What happens if this vent is blocked by a bookcase?

Ceiling fans are sometimes reversible, so that they drive the air8 wp4*tc2hzpw down in one season and phw8 pz42c* wptull it up in another season. Which way should you set the fan for summer? For winter?

Down sleeping bags and parkas are often specified as so maap/1e7qxkf 95nqqe -nny inches or centimeters of loft, th7ef qe/19kp nqnx -q5ae actual thickness of the garment when it is fluffed up. Explain.

Microprocessor chips have a “heat sink” glued on top that looks like a ser/j+u*0 (crugcdvp0 r jies of fins. Wjujvp (r+/*0cr0dugc hy is it shaped like that?

Sea breezes are often encountered on sunny days at the sewulci 7w(j m698,s4 8run br1err2lxhore of a large body of water. Explain in light of the fact that the temr re8rln98wlx12 cu,s 7jb u iwemr6(4perature of the land rises more rapidly than that of the nearby water.

The floor of a house on a foundation under whmm*:r efot .e/ich the air can flow is often cooler than a floor that rests directly onm:tofe/m.*r e 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 with the thermomcj;mitor8x mdo(2c5 bn7,cp- eter in the sh2bxm-7mc,tp ;58n j ociord(cade.

A premature baby in an incubator can be dangerously cooled even ws.fv)3 ewy4*wn-tyeb3o 9 wxzhen the air temperature in the ince)f* ve- nxwz wysy4wtob3.39 ubator is warm. Explain.

Why is the liner of a thermos bottle silvered (Fig. 14–15), and why does it hsvj c wms5fnquka(f(p) 4ah *q+j8c*3ave a vacuum bep*vh*4u3sj ( )(fa+sqfk8j5 a c wmqcntween its two walls?

Imagine you have a wall that is very well insulated — it has *x rm*zgm,kp.vi5kl )dz 4fmze8j 3(c a very high thermal re ,)fz lz4 8m(cv gkxdep3*ir.5j*mmkzsistance, $R_1$ 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 thon ca1oamter;tjp+ 8.h5mb7; e following 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) the mechanism(s): conduction, convection, or radiation? (b) 78+t ;ecb ap ;1ajo5hnmmto.rHeavy curtains reduce which of these heat losses? Explain in detail.

A piece of wood lying in the Sun absorbs more heat than a piece of sgap( ,8g efnp)916n 1ajtvjo shiny metal. Yet the wood feels less hot than the metal when you pick it1 noajn96 gp gft1p,j8sv()ae up. Explain.

The Earth cools off at night much more quickly when the weather is clear tlc*d(s gjs t6.ns0/gahan when clougl*td.6cs /0ags jn s(dy. Why?

An “emergency blanket” is a thin j2) mqz5 i;mj ccgeh81shiny (metal coated) plastic foil. Explain how it can hjc8 j5qc; giezh)m2m 1elp to keep an immobile person warm.

Explain why cities situated by the ocean tend to have lj5j sf2y:i1z q o 2+wqiitk/4bess extreme temperatures than inland cities1 :iqtk jfz 2qo+i 5yij2/swb4 at the same latitude.

  How much heat (in joules) is required to raise the temperatureigon)h4d7y a-u . ubh.ze 47ea of 30.0 kg of wate y )goeu7 44-.zb7ndhhui eaa.r from 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 iwk q4(k14k h8:oaqee 1w.hiy *kb/u wonitially at 1 a 8b44w.e(k:hkwo1oqyw khiu eq/1* k0.0 $^{\circ} C$ ?    $^{\circ} C$

  An average active person consumes abkx 1nw5+l0lae out 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 spzm 0+ imo19qbe w,1dlstx/e:)emj2i ystem of units. One Btu is defined as the heat needwpe/i9t x zmmio1 1 +me:)2leq j,ds0bed to raise 1 lb of water by 1 F $^{\circ} $ . Show that
1Btu = 0.252kcal=1055J

  A water heater can gewwg2a*ht:+zqdz +mb euze +n41ho6) v4h:ckdnerate $32,000\,kJ/h$ 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. Estimateq g le3y44a2nro)nbc/ how long it will take to heat a cup of soup (assume this is 25l)cog23 rqb4a ynn e4/0 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 120.iq/1xv +e-qrryy tiv)usa6 20-kg car yri./vxqeas t- 26q1+)iru v yto rest from a speed of $95\,km/h$ ?    kcal

  An automobile cooling system /*e4vvr6esyf holds 16 L of water. How much heat does it absorb if vee yr*f64v/ sits temperature 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 is needed to . .mrz1h7aaisraise 5.1 kgh7 amrz..1isa 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 teld6/k dy6li ze(oq,05kgns 4u mperature rise when they absorb the same amount of heat. What is the ratio of their masses? [Hint: See Table 14–1.yg(uk,e lsi06 kd5o dl/n4z6q]$m_{Cu}$ : $m_{Al}$ : $m_{H_2O}$ =    :    :   

  A 35-g glass thermometer reads 21.6wk(j 3kx 6njd;$^{\circ} C$ 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 clar79 of) wd9a 245-g block of copper at 285$^{\circ}C $ is placed in a 145-g aluminum calorimeter cup containing 825 g of water at 12.0$^{\circ} C$ ? $T_{eq}$ =    $^{\circ} C$

  A hot iron horseshoe (6e(1 wrinmg(y 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 substes(je0v( o:o mance is heated to 330$^{\circ} C$ and then plunged into a 105-g aluminum calorimeter cup containing 165 g of water and a 17-g glass thermometer at 12.5$^{\circ} C$ . The final temperature is 35.0$^{\circ} C$ . What is the specific heat of the substance? (Assume no water boils away.)    $J/kg \cdot C^{\circ} $

  How long does it take a 750-Wzd imlsc4n5;k 9xb;ff qk* 11s coffeepot to bring to a boil 0.75 L of water initiallykz5xfilb*q 14s mk scd;n1;9f 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 of7-lnc a2;u8xg 8uxjwt 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 water contai8u7nt -x8 waxg uj;cl2ned 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 +u li da)1q.q,)gwxj biron 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 h)f)cny3 c tav+0x:jgj kfrb-sh .6ov+ammer 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 amount o7p t56cbsv*h:9dwchgf heat needed to raise its thpct 695g:dh7cwb vs *emperature 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 d, gv+1 mdobn-q tpg)xif1b2*jj,t -))zp dny that is initially at 20$^{\circ} C$?    $ \times10^{6 }\,J$

  A 0.095-kg aluminium sphere 1 sjmgwk m51td68y/ w .6v e4r zfspcj99i2yljis 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, / jm4ms le1yjtcw5ki9.yzsd 9 6rw2gp6v18fjwhat is its temperature increase?    $C^{\circ}$

  During exercise, a person may give off 180 kcal of heat in 30 min x:(wvmfn5m o* by evaporation of water from the skin. How much water has been loxmfw *(:nmvo5st?    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 mqdo7fenm0c mc44za)i:c 1d8 z elting point is dropped into an insulated container of liquid nitrogen. How much nitrogen evaporates if it is at its boiling point of 77 K 84qz40d):1mo zcce m f7nadi cand has a latent heat of vaporization of $200\,kJ/kg$ Assume for simplicity that the specific heat of ice is a constant and is equal to its value near its melting point.    kg

  A cube of ice is taken from the freez q8eq1bn8b)wr pbl-vnk- o6h8er 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 wa+ny r+;p.toe gter 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 fp/v(gsu/f )gq.h d5moour 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 5gp)dm u qhgvf.o//(s? (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 10yzg8r 43vn6chr sc1qpxoy:,4 cy3s)b 0$^{\circ} C$ 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 me pw00f6x0enhircury 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 atbkdt4og z-tw re 7k zf(,cir426cd 7h( $250\,m/s$ 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 vwz2ci8rxs 3ck xbos1w 3x6a /dx+6t,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 thamu2wt* yzrem6g vg;9 9 u(d1fnt was stopped in a doorframe apparently melted completely gyfz9r;wu v*nu tm(2egd1 9 6mon 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 aluminun *bus1i*v:eta p 6)u*c/tp pjm 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 ga:yi+ao41z fw*w8(sd k7enpin Example 14–10, assuming that there are std pg f4 w(s 7wiy:a+8keoz1a*nrong gusty winds and the external temperature is -5$^{\circ} C$   $ \times10^{4 }$ W

  (a) How much power is radiated by a tunge s1t07j:m8euk nfm 1zsten 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 condk+jnd p+dtqd66l*1q axod 6:puction from the blood capildoddx++pq:1 *p jtlqnk66d6 alaries beneath 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 fae7/30tkevrside, share a 12-cm-thick brick wall. Because of a number of 100-W lightbulbs in one room, the air 0ef ertva/3k7is 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 of ice 3kd8 h6mbmjd)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 aluminj3qvocy-0tre,t 1etwsxj2ire 2q 3-1 um rod of the same length and cross-sectional area are attached end to end (Fig. 14–18). The copper end is placed in a furnace jcxirv-s e 21yt- e 0133otr e2qwqj,tmaintained 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 reefpk(3m8;+ , rnbxhqics5) zw.qnoz+ ceives eho,.zn(e f mbp8kqn + x53ci s);qr+wznergy 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 dissipated through a gla(wff6r v-qw3 a2:yysmuf 8i t9ss bulb that has a radius of 3.0 cm and is 1.0 mm thick. What is the differencer:v26i8ymwfuw st y-(f9f qa3 in temperature between the inner and outer surfaces of the glass?   $^{\circ}C $

  Suppose the insulating qualities of the wall of a wopqam0qu+4jk:.gc lbn( -c+ house come mainly from a 4.0-in. layer of brick and an R-19 layer of iq:j+ qlk g+c.pma0uobc(4w- n nsulation, 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 hasov;wi7dmmiv 12w 6pq)wt * /lx two panes of glass separated by an air space, Fig. 14–20. (a) Show that the rate of heat flow through such a windvxw2o7/ lqmm 1 dw*;t)vwi 6ipow 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. 399 p+,my4y sjwl atx 8.+xflfo4lhgt)asww,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 cony y9xayp81 2yytains 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 ind ba/i(j6t063dfvx lp the world’s oceans, estimate the heat liberated when a cube of ocean water, 1 km on each side, is cooled by0 d /xi6v(tpdfaj3b6l 1 K. (Approximate the ocean water as pure water for this estimate.)    $ \times10^{ 15}\,J$

  A 15-g lead bullet is8 +m att-3. ead r0e7 nitr7t7wew:dsf tested 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 syste td8 itama3e+w7s nwt7-rt. 07fdere :m 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 Sik;9mc6w+fd39trry qc61 h dyun, assuming it to be a perfect emit6 ;1dymr6tkccw+39i rd yhf9qter 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 persoyb hbhm oz g8.1 z-g-qmx;r;+dn 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 o:)r3hbatp /qjff the top of a cliff and falls a vertical height of 140 m before striking the ground.:qtr)j abp/3h Estimate the temperature rise of the rock if 50% of the heat generated remains in the rock.    $C^{\circ} $

  A 2.3-kg lead ball is dropped into a 2.5-L insulated pail e42l nx8ic8p3sf4xn pof water initially at 20.0px elxp4c438ni28 s fn$^{\circ} C$. 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 thick wit, )ehqv+tya f+qvd1rg b w(+j*h total surface aref qv +*qwrh1)j vetbga +y,(+da $1.2\,m^2$ 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 metabolism ra p3/(tna9h*d0v 52r dhrh aanwte 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 cc1s cup .t4(tkan be conducted from the interior of the body to the surface. Assumek.tsc1p ( tc4u 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-insulate o +q+as:rj1buofc 6k6d walls 17.5 cm thick (assume conductivity of air) and are r+obc6:o6kq1au +jsf a $410\,m^2$ 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 traven2 f:b6g7ti x60zi4iw shbed5ling 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 theow0se:k3k k7u leaf to calculate how much water must be transpired (evaporated) by the leaf per hour to main :okeu7kksw3 0tain a temperature of 35$^{\circ} C$.    g/h

  An iron meteorite melts when it; p4r6n)9 w5mntk.awjpca cz 3l 6bk1v enters the Earth’s atmosphere. If its initial temperaakc6k 45bpn lnw3)pjw .vr z;tc9a6m1ture 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 abgw 6fh: )8lgynsr 3kn1out 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 rubber byjy -pd v qd,ak9.sg9r(u tg-(all at a wall until they are about to drop due to dehydration and exhaustion. Assume that the ball hits the wall at a velocityg, dtsvpu(9.dj ygra 9k (--qy 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 massesabqhgxe2v p)hy) ; 6)g 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 a0y*n2uir u xj03r h;cxr14mdkt a rate of about 200 W. Estimate how long it would take for the body tempe*u40kxrn;3x01i2y j cr dm uhrrature 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 in255tonvg*g sh the 50-gal (185-L) water heater. This suggevg2sn5o5h g*tsts 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 surfa*abs1gtp g pye/u-kf( cw; royf: n)u 1.:dv.ece 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.    $^{\circ} C$