What happens to the work done when a jar of 7zsh9/-e8c vxuz en o a;83oowno iu24orange juice is vigorously shaken?

When a hot object warms a cooler object, does temperature flow between/;)ynyx(uw hv them? Are the temperature changes of the twxn/vyhuy;) ( wo objects equal?

(a) If two objects of different temperatures are placed ink*kz un,u 0bf ouik+-; contact, will heat naturally flow from the object with higher internal energy to the object with lower internal energy? (b) Is it possible for heat to flow even if the internal energies of the two objects are the same? Exp;+kz 0 -,unkuifkuo*b lain.

In warm regions where tr3ssjgy2rj;cfg*t n1 6 -aig )o7jpy2yopical plants grow but the temperature may drop below freezing a few times in the winter, the destruction of sensitive plants due to freezing can be reduced by watering them in the evening. 6jy-)g1j 7fng3 *yg c2yiorpja s;st2Explain.

The specific heat of water is qyis*22e i. csfuite large. Explain why this fact makes water particularly good for heating systems (that es2s*f.ci2 y iis, hot-water radiators).

Why does water in a metal canteen f u (usw 6p,m4qhg(3pjstay cooler if the cloth jacket surrounding the canteen is kept moif hpu3wq,u6gjps (m4( st?

Explain why burns caused by steam on the skin are often more severy)gatt:-nm87v;f hpwj k0k rc c,2/yse than burns caus; /fv-7 wprnct ,8sychj k:)a mkg20yted by water at 100 $^{\circ} C$ .

Explain why water cools (its temperature drod 1ej8)ft s.wei7d/sp+8 woylps) when it evaporates, using the concepts of latent heat a8 stl/js8+ peyw)i.ed fwo71dnd internal energy.

Will potatoes cook faster if the water is 9z ypwpoad y5ry-ic(h 1 pv:8,lw5;sb boiling faster?

Does an ordinary electric fan cooh z +f6vp/v+d,v)gzsnl the air? Why or why not? If not, why use it?

Very high in the Earth’s atmosphere, the bnvqey5 3zgwq:- 5z 1utemperature 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 covering themselvesbiy)b ra;r0 x7i06v xc:u/ voq with snow. Why would they do that?icb x:yro ;6xqu/0r v )v0b7ai

Why is wet sand at the beach cooler to walk on3/m hazuv54u y than dry sand?

If you hear that an object has “high heat con)oi sd+m z:+b, e+dcnktent,” does that mean that its temperature is high? Explain.b+sc+ d idk)+on:em, z

When hot-air furnaces are used to heat aut loegh-.aj6+8+024ts i/a kekkyzi house, why is it important that there be a vent for air to return to the furnace? What happens if this vent is blocked bazgy0el8h+ +jit a4kk ko ues2/6.i-t y a bookcase?

Ceiling fans are sometimes reversible,*4l 0fsvdkgfcf-eeu xs: ) .+g so that they drive the air down in one season and pull it up in av .+fcggd)sl*s0 :ue4-fx kf enother season. Which way should you set the fan for summer? For winter?

Down sleeping bags and parkas are ofgk /c9mxs/-sj 6l )hpdten specified as so many inches or centimeters of loft, the actual thickness of the garment when it is sd/lg-c69 mhp/xk j) sfluffed up. Explain.

Microprocessor chips have a “heat sink” glued on top that looks like a series 5x0o *z e3itfs ioc))softf)e 3 oscixiso0*5z) fins. Why is it shaped like that?

Sea breezes are often encountered pn n/; oa0v9*xk(wzpb on sunny days at the shore of a large body of water. Explain in light of the fact that the temperature of the land rises mb0 (ozp/nx;p n k*av9wore rapidly than that of the nearby water.

The floor of a house on a foundation under which tf f3x-,l vijk4he air can flow is often cooler than a floor that rests directly on the gr ,j 3kv4i-xlffound (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 t5uwmj69z pt 7o sa2z/ysx(vk 5hermometer in the shj tz (sk27o9wymz6p5sx vu5/aade.

A premature baby in an incu68m.h/ky7m wvbvpdk k)+ta; )2ay s +nqm 6euabator can be dangerously cooled even when the air temperature in the incubator is warm.v 26+7m)aeq/mdky )kua s+m ;wh6tvybp8k na . Explain.

Why is the liner of a thermos botbf/ c1 3 *rnhxlxnxe- 8tvsg:,tle silvered (Fig. 14–15), and why does it have a v-g/nxxs1*n3e htr,:lc 8bf x vacuum between its two walls?

Imagine you have a wall that is very well insulated — it has a very high t* -6fjs/4kjss ) o-vpenr*na lhermal - o-f ns4al)k6njssj*er /vp *resistance, $R_1$ 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 khe cu :jy;.,sby 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 radiation? (b) Heavy curtains reduce which of these heat losses ;h.cj, kues:y? Explain in detail.

A piece of wood lying in the Sun absorbs o*spk8nhk ,p 8more heat than a piece of shiny metal. Yet the wood feels less hot than the metal when you pick it up. Explainp ,pns8ho*8kk.

The Earth cools off at night much more quickly whuz7)u. 26 vfh1jyjahnen the weather is clear than when cy 26fn zhauj7hu 1j)v.loudy. Why?

An “emergency blanket” is a6nsg ( +2czpw 9/sjwgc thin shiny (metal coated) plastic foil. Explain how it can help to ke+gg w(2znc6pcs/swj9ep an immobile person warm.

Explain why cities situated by the ocean tend to have less extreme temperay 9 lbu8qji,um1wc8b 2yp4+hutures than inland cities at the salqy81ip8 c jm+wb924bhyu uu,me latitude.

  How much heat (in joules) is required to raise the temperature of 30.0 kg of wat-03pffniyy5 8gr*zegp):vbh er from 15e nb8gg yr3f0)pyi -h v*pf:5z $^{\circ} C$ to 95 $^{\circ} C$ ?    $ \times10^{7 }\,J$

  To what temperature will 7700 J of hea jy0 :ysb/dm+et raise 3.0 kg of water that is initially y0bs/m:ej+ydat 10.0 $^{\circ} C$ ?    $^{\circ} C$

  An average active person consumesirr 0rglttp2 k168z)d about 2500 Cal a day.
(a) What is this in joules?   $ \times10^{7 }\,J$
(b) What is this in kilowatt-hours?    kWh
(c) Your power company charges about a dime per kilowatt-hour. How much would your energy cost per day if you bought it from the power company? Could you feed yourself on this much money per day?    dollars per day

A British thermal unit (Btu) is a unit of heat in the British system of8t;q,cb f5 h o.egew;a units. One Btu is dewq,b aoe.;;te5fcg8 hfined as the heat needed to raise 1 lb of water by 1 F $^{\circ} $ . Show that
1Btu = 0.252kcal=1055J

  A water heater can gj9s sqtj23 )jtenerate $32,000\,kJ/h$ How much water can it heat from 15 $^{\circ} C$ to 50 $^{\circ} C$ per hour?    kg/h

  A small immersion heater is rated f6-1gblblrh).m t ih-me r g7,at 350 W. Estimate how long it will take to heat a cup of soup (assume this is 250 mL of water) from 2m-tr lg1 g6)f 7,b-ihhm.brle0$^{\circ} C$ to 60$^{\circ} C$ .    min

  How many kilocalories are generated when th*2/qecih8 1a5 fwcy aae brakes are used to bring a 1200-kg car to rest from a speed ah1wc/fia5ey8c *a 2q of $95\,km/h$ ?    kcal

  An automobile cooling system holds 16 pb ww ig1ab/ 3uck*ps052;gdcL of water. How much heat does it absorb if its temperaapb/5g u c; b0 wp*gs2dc1kw3iture 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(;b1ynuu fb +v heat is needed to raise 1bfunv;+yb u(5.1 kg of the metal from 18.0$^{\circ}C $ to 31.5$^{\circ} C$ ?    $J/kg\cdot\,C^{\circ} $

  Samples of copper, aluminum, and water experience the s 3f)soln64tyj0amap pa)z kh*) f2n;fy7r5 cy ame temperature rise when they absorb the same amount of heat. What is the l; sf)fz3at)2 56pa j7pa*4 yr cym)o0fhynnk ratio of their masses? [Hint: See Table 14–1.]$m_{Cu}$ : $m_{Al}$ : $m_{H_2O}$ =    :    :   

  A 35-g glass thermometer rea . hecl-c8 kdl4f8vkwb ;lag))ds 21.6$^{\circ} C$ before it is placed in 135 mL of water. When the water and thermometer come to equilibrium, the thermometer reads 39.2$^{\circ} C$ . What was the original temperature of the water?$T_{iH_2O}$ =    $^{\circ}C $

  What will be the equilibrium temperature w6 t q++f7 ci0qn)wogqwhen 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 (mass = . -gv7qun c jaa:ap,4p$0.4\,kg$) 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 heated f n*o.5ho(+x 4xekz rnto 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 in*wg f6q6eu1v ac +jcx/itiaf1e+w6ug 6xqaj vcc/ *lly 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 of candy from the following measudjt1*x 5p1k kurements. A 15-g sample of the candy is allowed to dry before putting it in a bomb calorimeter. Theupxk 5jt11d*k 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 o5 0 dy,zs.nbh180$^{\circ} C$ 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 p5a g)rr pf3h+hammer 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 anuq te5d4-. igb dfk-6xae/40 vk4d/tpl tovu) object is defined as the amount of heat needed to raise d)4.kdttlv /pxde 4ti fv -kegu/0q6bu- 54aoits temperature by 1 $C^{\circ} $ . Thus, to raise the temperature by $\Delta\,T$ requires heat Q given by
$Q\,=\,C\,\Delta T$
(a) Write the heat capacity C in terms of the specific heat, c, of the material.
(b) What is the heat capacity of 1.0 kg of water?    $ \times10^{3 }\,J/C^{\circ}$
(c) Of 25 kg of water?   $ \times10^{ 5}\,J/C^{\circ}$

  How much heat is needed to melt 16.50 kg of silver that is 02jy bxtrzqhs;(1s)p initially at 20$^{\circ} C$?    $ \times10^{6 }\,J$

  A 0.095-kg aluminium sp3zd. wu iop5ux:7 k4mohere 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 sphere, what is its temperature id oxw:k4.3ou7 mp uz5increase?    $C^{\circ}$

  During exercise, a person ma k lv3;/ro lh 8bqgb*ur6u ze5*,+ r4u)jyvxgoy give off 180 kcal of heat in 30 min by evaporation of zvexuubrgj*ro*r ql;/85h3)6 b lg kuo+4y,vwater 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 conta:9yrtaly67sdi +0opilp 4 w6liner of liquid nitrogen. How much nitrogen evaporates if it is at its boilingt497p6wod+0sl 6i :alypi lyr 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.il pvo6v2s(pbl6h g *)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 kz8x2,q-pb wb 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 bicyclistszq:uto(3yg t-0frss x*)b-z consumes 8.0 L of water over the 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 kcalt:qz*tsx3frboz (u s)g0-- sy 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 a9)se zx t+qp*zky.r-f cf.h*ct 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 memlo jg 0 nmh66c7 ksxr;9m.u/ircury 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 travel l,nxcu5)kj a,z7brq9ing 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 moving a ba2)sf*fp i7tt $6.4\,m/s$ 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 lp;ws juaht*ns)p9ae +:q 5 q5fead bullet that was stopped in a doorframe apparently melted completely on impact. Assuming the bullet was firedh:qs)f5*nes p wqapa;tj95+ u 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 withnvzs dq2;97kd d-euc9 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 condu .o0fh0roh;ct ction in Example 14–10, assuming that there are strong gusty win r.ohhc00fot;ds and the external temperature is -5$^{\circ} C$   $ \times10^{4 }$ W

  (a) How much power is radiated by a tungsten sphere (emisso mnr)zb9o p2/ivity $e\,=\,0.35$) 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 he5/dt -, f cwrfxw),swjat flows by conduction from the blood capillaries beneath the skin to the body’s sw,xfws,d c/wtfrj)- 5 urface 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 12i wxsf3 91qmz(9n kf-c-cm-thick brick wall. Because of a number of 100-W lightbulbs in one room, the air ik-m (99nz f xs3w1cqfis 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 ycf h5.k3e +xsp :xqn6Sun to melt a 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 alw w9thr c00 3nwe-oxd4uminum rod of the same length and cross-sectional area are attached end to end (F owhr4ce0 wdt0nx39w- ig. 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, eq:.dho pr ef )gn4 eb,1wnp1e2stimate the rate at which the whole Earth receives energ deb2gpn h1ef. ,rpqw:ne1) 4oy 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 gefs o q*6;jnmopg2sko s2: 6n)jnerates 95 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 the difference in temperature between the inner and outer surfaces o*n6pkoosjg:n6 ;j s)m qs22fo f the glass?   $^{\circ}C $

  Suppose the insulating qualities of the wall o8chidcr 9;lyws :n9u2f a house come mainly from a 4.0-in. layer of brick and an R-19 layer of insulation, as shown in Fig. 14–19. What is the total rate of heat loss through such a wall, if it:y 89ir2 lccsd;9 nwhus 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 dv*l( xtp: r;zseparated by an air space, Fig. 14–2rt z:v;dxpl*( 0. (a) Show that the rate of heat flow through such a window by conduction is given by
$\frac{Q}{t}$ = $\frac{A(T_2-T_1)}{l_2/k_1+l_2/k_2+l_3/k_3}$,
where $k_1$,$k_2$ and $k_3$ are the thermal conductivities for glass, air, and glass, respectively. (b) Generalize this expression for any number of materials placed next to one another.

  Approximately how long should it take 11.0 kqmd)+gm a/5j0y/ adotdj3 :aog 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 contglvc wa9, +l;tb-rjnh,j ow :-ains 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 in the world’s oce9ore 0 1(y pca3eotot6ans, 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(oa6 93toc 0ey oeprt1 pure water for this estimate.)    $ \times10^{ 15}\,J$

  A 15-g lead bullet is tested by firing it into a fi6kx*:dl:al yexed block of wood with a mass of 1.05 kg. The block and imbedded bullet together absorb all the heat g edyakx 6:l*l:enerated. 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 7x :m,gwr8wgkllm2 1h Sun, assuming it to be a perfecm :g,2h1lxw grwmkl78t 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 xr3s r6y( 3zyj*d;zpuk k3(z7 hy:f xl70-kg 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 rollrsq62-e/ vmq: u x(xwms off the top of a cliff and falls a vertical height of 140 m before striking the ground. Estimate the temperature rise of thexrv2(mx-m: weq sq u6/ 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 insull m5 bm6 b5rpn;h6 w/.0hlsncx8cn /hjated pail of water initially at 20nb . pc8bh l5w hmj6nmr0 ;/6sn5lhxc/.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 jack)w5 2c:fdhg8rb lthw 6et 3.5 cm thick with total surface area ) h6rt fh lwdb2:w85gc$1.2\,m^2$ 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 rac pjacq+ou*+;mfrx6p1;b5 1ax3 qg nyte 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 theda:tfu y g *du)6 lmvzptz(y8g6um:.+ interior of the body to the surfaca 8fl tzptmy+m6(yu zu)6: ggd*u:vd.e. Assume that the thickness of tissue is 4.0 cm, that the skin is at 34$^{\circ}C $ and the interior at 37$^{\circ}C $, and that the surface area is $1.5\,m^2$ Compare this to the measured value of about 230 W that must be dissipated by a person working lightly. This clearly shows the necessity of convective cooling by the blood.    W

  A house has well-insulated walls 17.5 cm thick (assume cons6emzr k77lh s( x/ )aris7:+jks l(jgductivity of air) and areal + msk/z(a67ihlkjjg )r:x77 rss(es $410\,m^2$ 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 travnv, +oyc-h. dveling 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 pa:bj7-ab py47:mh /gwh c-bfji.vc5 zgrt (a) in Problem 58, take into account radiation from the leaf to calculate how much water must be transpired (evaporated) by the leaf per hour to maintain a temperature ofc.j:aw/-7v7ih5hc -4 yf mjgg:bpb bz 35$^{\circ} C$.    g/h

  An iron meteorite melts when i lf pv25a)xm q1avf)5mt enters the Earth’s atmosphere. If its initial temperature was -12a5m5fv)2)lfva1mp xq5$^{\circ} C$ 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 Eart4qgctnx: hs,3h’s 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 hit a soft rubber ba0wx6nop c1f1wosy)3 qll at a wanwsp 3w0q)x1coo 6yf 1ll until 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 masses of ice at 0m7v4a9s qlx32of/ tix$^{\circ} C$ and steam at 100$^{\circ}C $ are mixed together?

  In a cold environment, a person can lose heat by conduction ando8jy3:z0ctcfmo) 3 sv radiation at a rate of about 200 W. Estimate hv y :mtj 3zfc)o38cso0ow long it would take for 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 in the htk1p0q)se4b 50-gal (185-L) water heater. This suggests qb)0h s 14kptethat the tank has emptied and refilled with water at roughly 10$^{\circ} C$. (a) How much energy does it take to reheat the water to 50$^{\circ} C$? (b) How long would it take if the heater output is 9500 W?    s

  The temperature of the glass surface of a 60-W lightbulx:ztz3fa,lvnkcgdb3 8 f)x)+b 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.    $^{\circ} C$