What happens to the work done when a jar of orange juice is vigorously sha9 ,2 b(xqbqi-eogha 9cken?

When a hot object warms a cooler object, does temperatureyk.0 8 ay1juao flow between them? Are the temperatur1 0k8uj.aoayy e changes of the two objects equal?

(a) If two objects of different temperatures are p*u 4hqh1aa/u2nkfg)+b ( p p+ gt(9urvsyk1dylaced in 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 f/r+p* 1y+t(ugn9 4v kuh kf(y )ua2dapqgh1sblow even if the internal energies of the two objects are the same? Explain.

In warm regions where tropichtqeo494 r8 mlf/w s8mal plants grow but the temperature may drop below freezing a few times in the winter, the destruction of sensitivt4hl mq8r9/ os8w4emfe 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 wate9ifi5tsr bx e qysk14)-,9b2keg z-pvr particularly good for heatinx5k-)yk ezevbf2s -q it1b9sip ,r4g 9g systems (that is, hot-water radiators).

Why does water in a metal canteen stay cooler if the cloth jad3 (u1xt s)wp0ry b-1wwm li+hcket surrounding the canteen is 3 bu1mpyxwis +hrw-wl(t0)1 dkept moist?

Explain why burns caused ah.,lnmh08 rp5:ceuqby steam on the skin are often more severe than burns caused by wate5e0m chra.,qh:8 nlup r at 100 $^{\circ} C$ .

Explain why water cools (its temperature drops kw;b/ln/s)tm93cy*t j (twwu3 u8lxsilv85 d) when it evaporates, using the concecmt btl)3 w/dlv;uksy93tn/iw lux8*s(wj8 5 pts of latent heat and internal energy.

Will potatoes cook faster if iv52;r eelyn0v yw5 i4the water is boiling faster?

Does an ordinary electric fan cool t4 clcc(mdtm,m(cu8s .he air? Why or why not? If not, why use it?

Very high in the Earth’s atmosphere, the o 6vnb,l 6maxj+j6-avtemperature can be 700 $^{\circ} C$ . Yet an animal there would freeze to death rather than roast. Explain.

Explorers on failed Arctic expeditions have survived by coveu gr+tcif+k wjhw1h0:08 tb 4yring themselves with snow. Why would they do th bt: wg0ty1 ujh0h++cr 84fikwat?

Why is wet sand at t(mp.siqky 0 9o 0w zcr4dh:n+nc(k4hkhe beach cooler to walk on than dry sand?

If you hear that an object has “high heat content,” does that meo fm1po3 w)n+y5t 6eo*fi dk2lan that its temperature is high? Exd6wo l+o) nfy*p3kifoe52 tm1 plain.

When hot-air furnaces are used to hea4;m mxe4bg (kqnj,a- :3ie,j ahtyhz. t a house, why is it important that there be bi3n-,hk (a meeg:y.4j 4m;jx hq,zt aa vent for air to return to the furnace? What happens if this vent is blocked by a bookcase?

Ceiling fans are sometimes reversible, so that they drive thp/ +o6uckkz f:8(r)lf.p)p)o5 g1 vxqgh esrje air down in one season and pull it up in another season. Which way should you set the fan for summer? p8kp qo6v csg1of)r/h + j)5glx.u)kze f:p(rFor winter?

Down sleeping bags and parkas are often specified as so many incho 7 ,;vkir :innutbf;7es or centimeters of loft, the actual thickness of the garment when it is fluffednki tnv7fbu ;:;ir, 7o up. Explain.

Microprocessor chips h9a x;m1.iz 6fhrw6ao lewc9o1ave a “heat sink” glued on top that looks like a series of fm w.ei16 laoa6rw c9x 9zhof;1ins. Why is it shaped like that?

Sea breezes are often encountered on sunny days at the shore of a largzwol8svi;n q7w*- 0kee body of water. Explain in light of the fact that the temperature of the land rises more rapidly87nzk0-ov *wiew lqs; than that of the nearby water.

The floor of a house on a foundation under which7vfo*ceyv,om t. fb u3978q gp the air can flow is often cooler than a floor that rests directly on .q7uto3g me,oc vf*f 8pv97 bythe 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 the1 0jp;a jswal/rmometer in the shade.p jl ;a0ws1aj/

A premature baby in an incubator c3dbip z7 a9(vman be dangerously cooled even when the air tempedpm7avz i b93(rature in the incubator is warm. Explain.

Why is the liner of a thermos bottle silvered (Fig. 14–15), and why does it havykox5 g9tvq7q5h bc:4 c3h;b he a vacuum between its tw5co79hqyvck5b 4; gt q:hbx3ho walls?

Imagine you have a wall that is very welx c4h0r 2s)u p;iblu6bhjq.:nl insulated — it has a very high thermal resistscphq )2il6 uur jnhb0:. bx;4ance, $R_1$ 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 windov;8lpc pll4 0rs6up(r 9afx2iws by the 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 radiatio ll4cpusp ra x2p(0 f8v9;6rlin? (b) Heavy curtains reduce which of these heat losses? Explain in detail.

A piece of wood lying in the Sun absorbs mozo b tua ,0 7ki3islu,gp07q+o6u1vb ire heat than a piece of shiny metal. Yet the wood feels less hot than the metal when you pick it up. Explain0sv7i3 b zotqgu6,klbo7,ua0p + ui1i.

The Earth cools off at night much more quickly when the weather is vr.hg ny03ptz8s p *kb5bwl*14mn(jx clear than when clo*bp j 5b* 08kwlgyxp.h rst1nvn3zm4(udy. Why?

An “emergency blankeg9y7f0k.tkgu 69 eigmt” is a thin shiny (metal coated) plastic foil. Explain how it can help to keep an immobile perso7gitk9e.u0 9g y kg6mfn warm.

Explain why cities situated by the ocean tend to h6)k 3dx fi(zh7yrzgu )ave less extreme temperatures than inland cities at the sa hr73kf)igzzd6) u(yx me latitude.

  How much heat (in joiyt5p i )l2hjk.ei9;s :fa7cn ules) is required to raise the temperature of 30.0 kg of water from:h jpnf 97)iklyie2i c.;t 5sa 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 i/o w2c u,r( /ligagh*ss initially at 10.hau gwc2(l/ /isg*,r o0 $^{\circ} C$ ?    $^{\circ} C$

  An average active person consumes about 2500 Cal a dairarcq- bttryr,g3(2a5sg.8 1 t. kody.
(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 oeh/3 km no.zs.ur 2kh5f units. One Btu is defined as the heath erho /z .5m3sn2kk.u needed to raise 1 lb of water by 1 F $^{\circ} $ . Show that
1Btu = 0.252kcal=1055J

  A water heater can gen51bl lylu)t o)hkv8/jerate $32,000\,kJ/h$ How much water can it heat from 15 $^{\circ} C$ to 50 $^{\circ} C$ per hour?    kg/h

  A small immersion hea(p 8 3z,imgkw. fdiv4oter is rated at 350 W. Estimate how long it will take to heat a cup of soup (assume this is 250 mL 3 z,d8o pimv( i.kfg4wof water) from 20$^{\circ} C$ to 60$^{\circ} C$ .    min

  How many kilocalories are generated when the brakes are used to bring a 1200-hqni lwgv(;,b )ci*xq109op ykg car to rest fromp 09l gi,w1vy qb*c;oqxni( h) a speed of $95\,km/h$ ?    kcal

  An automobile cooling system holds 16 L of water. How much heat does it absojdjgu c t.*hz1jvjkl;2: ,ic;rb if its temperature rizjujg.c: hd;jtc * il12;v,jk ses from 20$^{\circ}C $ to 90$^{\circ} C$?    $ \times10^{ 6}\,J$

  What is the specific heat of a metal ,m +i)fjlvvn/ /,knwj substance if 135 kJ of heat is needed to raise 5.1 kg of the metaj/nvif)+ m,,lv nk/ wjl from 18.0$^{\circ}C $ to 31.5$^{\circ} C$ ?    $J/kg\cdot\,C^{\circ} $

  Samples of copper, aluminum, and water experie/gaxnx9g q j 9a;2*narnce the same temperature rise when they absorb the same amount of hea9ng9 2a* xrxnq a/gja;t. What is the ratio of their masses? [Hint: See Table 14–1.]$m_{Cu}$ : $m_{Al}$ : $m_{H_2O}$ =    :    :   

  A 35-g glass thermometer readgkm( vm:nm,v4c b8-g df ffbwfhow 6r;-8)1 wbs 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 temperaturanw s8ilqp b 4s1ss,wfk skv2:d99d*h*,( uzqe when a 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 (mdqx0rfz,(* 2wubbl ntd: z9v+ ass = $0.4\,kg$) 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 y nykd+fgvxpb80 ) 5uwpu )hou+e *)x;substance 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 takgc-g:u42,to q c2ynq5d8h tgke a 750-W coffeepot to bring to a boil 0.75 L of water initially atqdqc5,ngg:h8tct - u2 4gk2oy 8.0$^{\circ}C$? Assume that the part of the pot which is heated with the water is made of 360 g of aluminum, and that no water boils away. $\approx$    min (Round to the nearest integer)

  Estimate the Calorie content of 75 g of candy from the following mlyq yz6e/qzc,ac -k,6easurements. 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 0.7y/ck,l ,z6qq- aezy c625 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 18aw *z3;qt* bibbfb( 5k0$^{\circ} C$ 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 speuu/ spr .(lf;2dm d4cued 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 of heat needed t5dxxy-*rljnp -m;ryyw+ p s4spu4// vo raise its temperpsrypy*lnw4xd/-j-5 x ;/ rys+mp 4 uvature 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 s / nte235ecztoilver that is initially at 20$^{\circ} C$?    $ \times10^{6 }\,J$

  A 0.095-kg aluminium sphere is dropped from the roof of a 45-: +i6eiz ft)ktm-high building. If 65% of the thermal energyt ):eitzifk6+ produced 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 hedxl8 w 36tny4-fs : 07gwigpnvat in 30 min by evaporation of water from the skin. How mu 6 ixlwdp87n:wy tvs3-g4nfg0 ch 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 insulated1 b: 1hy:0msdxdxg r0s container of liquid nitdy: xsh0:dr 1sb0xm1g rogen. How much nitrogen 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 the freezer at -8.5 aj0wyx)5.-o2ev qdjv$^{\circ} C$ 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 1;)khvnctzeo+c 0u 1xej/b5mwater 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 thdqj(bv9lpil- j; z02kj *n:sp e span of four 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?0zp(-p ;jqj: nklli*9jbvd2 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 1cn:cvdc* ;g azu7ngd ap31r) ;00$^{\circ} C$ 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 mercurf+9.buev9 cguy 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 at4yb;c* q8vf*xkj4e ql $250\,m/s$ 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 a17uskk ;q;oxv t $6.4\,m/s$ 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 foren0n5kz05abetpc, rs 0 fm, r3whsic investigator notes that the 8.2-g lead bullet that was sz0 r0wre0fkb,p5 5t h m3cna,stopped in a doorframe apparently melted completely on impact. Assuming the bullet was fired at room temperature (20$^{\circ} C$ ), what does the investigator calculate as the minimum muzzle velocity of the gun?    m/s

  One end of a 33-cm-long aluminum rod with a diameter of 2.0 cm is kept at vu lk /1n;zkz5t4zby5 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 bcdfg9(il r1 u:y conduction in Example 14–10, assuming that there fd (i:g1r9ulcare strong gusty winds and the external temperature is -5$^{\circ} C$   $ \times10^{4 }$ W

  (a) How much power ihh ze*n+p 5r 96ok8v fd7nan:zs radiated by a 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 skin.-o7zx yuc-cj ms: iyf:7eg.a6 m2 1huw Suppose 200 W of heat flows by conduction from the blood af ejc1 i. 7smwch-z2u m7 ox6-gy::yucapillaries 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 side, share a 12-0u 5:h u.d lgjoh04fbfcm-thick brick wall. Because of a number of 100-W lightbulbs in one room, the air is at 305gblfh u04oj:h .dfu0$^{\circ} C$, 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 x /yxkg6. x/ieat 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 rodmo8 :7g qn3x on,r;kzg of the same length and cross-sectional area are attached end to end (Fig. 14–18). The copper end is placed in a furnace mai8k ;m xg,zngo3on: r7qntained 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 whold8tt mf+h3cp- e Earth receives energy from the Sun. +m-3dhttpc8f   $ \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 95mizt 00svv(7/+wdyf.a;m z iq W of heat, which is dissipated through a glass bulb that has a radius of 3.0 cm and is 1.0 mm thick. What is th0 iayqfv /.m7+w; i0(zdmz vste difference in temperature between the inner and outer surfaces of the glass?   $^{\circ}C $

  Suppose the insulating qualities of the wall of a house come mainly from ao9x3 e.fim5rq 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 iiorm3 5.qf xe9ts total area is $240ft^2$ and the temperature difference across it is 12 $F^{\circ} $?    Btu/h

A double-glazed window has two panevz+ 75 a7ijsivs of glass separated by an air space, Fig. 14–20. (a) Show that the rate of heat flow through such a window by conduction az ji5v77v+si 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 s-eim2uw,u (u0$^{\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 0v.ix87d , q+yxn,srjw .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 containec,ddn .wcxlg m50x33vow-y m j: :4wged 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 3dw5w.lm gn:e vxcxd 0o,4wc g3-ymj :pure water for this estimate.)    $ \times10^{ 15}\,J$

  A 15-g lead bullet is tested -),92 v0m /i0 ue rdpbw8k8nnfbbdzyvby 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 measurz-u0bfmr8/d iy,8 kwn0evbpd vb2) 9ned as 0.020 $C^{\circ} $. Estimate the entering speed of the bullet.    m/s

  (a) Find the total power radiaun7(cuv7 m. qa-yl;7ga xthm8jsv88 ited into space by the Sun, assuming it to be a perfect emi-yn8hs;a.vj (xatu88il vmc7 gu 77qmtter 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 gvv0e f3qqmd5c j4y,3 venerate $200kcal/h$ 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 ver2 jzl;;g)s zxvcz;xm-uqu 5+vjq )tw-tical height of 140 m before striking the ground. Estimate the temperature5czw2z)l; -+-qg jmsv ;xu)vq;x tuj z rise of the rock if 50% of the heat generated remains in the rock.    $C^{\circ} $

  A 2.3-kg lead ball is 4 55;tfyxqek;o(r8c r*pt*j dr x,vufdropped into a 2.5-L insulated pail of water initially at 20. 8tx;d tu (f 4eq,ok*r*5;cyjv xrrp5f0$^{\circ} C$. 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 x:d0:esu lxnfj/ ;ui/a goose down jacket 3.5 cm thick with total surface area /0fjxd:u/xs i: nu;le$1.2\,m^2$ 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 met9w0 xt-/p,xlpg idpa3abolism 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 the bodi 0k8+yrl 9tos7:f (pbaeca d(y to the surface. Assume that the thickness of tissue is 4.0 cm t8a(lre(+ 09p 7adi:cksbyof, 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 wa ng2squ2y7*s+ hdt*y2.orn xplls 17.5 cm thick (assume conductivity of air) and are.gs orx 2*7sy+*tun2 y qpd2hna $410\,m^2$ 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 traveliefe a xytmyg p66n,-qt p4)h16ng 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.pdhql;c vfq (v xu969 from the leaf to calculate how much water must be transpi.fdpvu69q(xvl9ch ; q red (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. tg /af15nrr8/uty50v ftm b4 lIf its initial temper8r l/0y1u avf4trntf tm5 bg/5ature 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;4qhewwvyfz7 0v 2w /p 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 ;i2tq (n4v fio a8/ivshit a soft rubber ball at a wall until they are about to drop d(; oi/v28 tvnqf iia4sue 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 finam(kl s sw n+gzpe55k96l 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 cam0zd.s5nwjc ne 2p))lzj 7z0 xn lose heat by conduction and radiation at a rate of about 200 W. Estimate how long it would take for the body temperatez x )d0 cj.w5l)20mpzzn 7jnsure 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 dishw3ioa.d t7asx*.v *8sg7e 1c pdwq 6ffpashing, there is “no hot water” left in the 50-gal (185-L) water heater. This suggests that the tank has emptied and refilled with wafv dacxg oip71 pqd*s.6* aef83ts7w. ter 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 surhmzr2 fl7u +*zface 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.    $^{\circ} C$