What happens to the work done 9zi o.et;aoxq+7jakffr ks/)2xk);w when a jar of orange juice is vigorously shaken?

When a hot object warms a cooler object, does temperature flow between t/f6k90pit4dtjpm4z l8+ta :3n dfdrdhem? Are the temperature changes of the two ot:p ndj8 t4 imzda0pd4lf9dr6/3ktf+ bjects equal?

(a) If two objects of different temperatures are placed in contact, will hy1w/c ; lcxk:geat naturally flow from the object with higher internal energy to the object with lower internal energy? (b) Is it possible for heat to fg :cxk1 lyw/;clow even if the internal energies of the two objects are the same? Explain.

In warm regions where tropical plants grow but th;e4a.l +bfro9hqr 9gee temperature may drop below freezing a few times in the winter, the destruction of sensitive plants due to freezing can bfgrlraq4e99 e .h +;obe reduced by watering them in the evening. Explain.

The specific heat of water is quite 2js5.oh e/x n (0hw) *1qsi,mcqyobnjlarge. Explain why this fact makes water particularly good for heating systems (that i j0o2nq ,nmej* 5(qyshh/ib1 cx.s)wos, hot-water radiators).

Why does water in a metal canteen stay cooler if6g5op)od 3r moo3evvr o75,b o the cloth jacket surrounding the canteen is,o7r3)og oo3p 6bevdvo5 ro5m kept moist?

Explain why burns caused by steam on the s6 9he+yawq1n9y0m veyrmob,ny 1a.*qkin are often more severe than burns caused by water at 1 yn,.ebmq*o1 av19 ehqnmya 09y6ry+w00 $^{\circ} C$ .

Explain why water cools (its temperature drops) when it evaporates, tny)5 e*) exgtusing the concepts of latent heat and internal e)ne y5t*x tge)nergy.

Will potatoes cook faster if;zhqfuny ,2t my6 zb- t9y33ly the water is boiling faster?

Does an ordinary electric fan cool the aik 9bjn/eg( q9sf1.jwup6 h 6ebr? Why or why not? If not, why use it?

Very high in the Earthix:(tf3fg8stvkp ( m+eni6+g ’s atmosphere, the temperature can be 700 $^{\circ} C$ . Yet an animal there would freeze to death rather than roast. Explain.

Explorers on failed Arctic expeditions had6u(nkk p55ge herb9.ve survived by covering themselves with snow. Why would thde5kkgh(. p 5runb6e9 ey do that?

Why is wet sand at the beach cooler tohcek u3wj,/q1 walk on than dry sand?

If you hear that an object has “high heat)c1 fqun5 sos) content,” does that mean that its temperature is high? Eo cnsq)f) s15uxplain.

When hot-air furnaces are used to heat a house, why is it importanxq6xapqkk3d3i)e v z d spz.7x;rj (*)t that there be a vent for air to return to the furnace? What happ k i*(x;zzjep))pxv xkqqs733r6da. dens if this vent is blocked by a bookcase?

Ceiling fans are sometimes reversibx rtjk:74gde 6le, so that they drive the air down in one season and pull it up in another 6r7 :et4dj gkxseason. Which way should you set the fan for summer? For winter?

Down sleeping bags and parkas are often specified as so many inches or r dc a09g6mb)g8i-wehv+e.xrcentimeters of loft, the actual thickness ofe6h+eir awm08dgvb c g)rx -.9 the garment when it is fluffed up. Explain.

Microprocessor chips have a “heat sinxdbzl1i(/fh)s2k3f .b/zmde k” glued on top that looks like a series of fins. Why is it shaped like 2 1dmi3kh/ l efbfb). zd(xs/zthat?

Sea breezes are often encoun9af apc*g 3rt(tered on sunny days at the shore of a large body of wp*9 c(argt3 afater. Explain 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 thek)ce glo7fy4+h/f4y l air can flow is often cooler than a floor that rests direy)yl +/4ohce 7 lffkg4ctly 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 with the thermometerf;;3fbg v,:st6k wwul in the shade fsbk,t63l:fv wu;w g;.

A premature baby in an incubator cj0.f3ojsr km (an be dangerously cooled even when the air temperature in the incubator is warm. Explf 0jr3j.msk (oain.

Why is the liner of a th97wuyduy3r6 w c;q5 mnermos bottle silvered (Fig. 14–15), and why does it have a vacuum between its q56ww rn7;mu3y9d ucytwo walls?

Imagine you have a wall that is very well insulated — it has a very high thermat/1 /6 e2s;9bxzsrg 1ettf9hjunhz u :l resistance,6h/9bthe tg/nss: u jr2zef1x1 u t;z9 $R_1$ 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 thro , 1+cyevqtw, f:tu6qyugh windows by the following processes: (1) ventilation around edges;v, 1:q+tcfy u ewq6,ty (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? Explain in detail.

A piece of wood lying in the Sun absorbs more71(sii q by+ bb.ydz-h heat than a piece of shiny metal. Yet the i7 dqb(y+1bs zbyhi- .wood feels less hot than the metal when you pick it up. Explain.

The Earth cools off at night much more quickly when the weather is clear than i 5moey yb aj0xp6wk55 o*:v)jwhen clo mkj6ywo x0bj: op5a *55ye)ivudy. Why?

An “emergency blanket” is a thin shiny (metal coated) plastic foil/wt64igg+z+sbr c( tu . Explain how it can help to keep an immb4 (rszu+cg gw/+ti t6obile person warm.

Explain why cities situated by the o nb6:,e fgjlm6x65zp.3q vnug2-kzv fcean tend to have less extreme temperatures than inland citikne26g-lfn3jzgubvfz 66.:v p5m , qxes at the same latitude.

  How much heat (in joules) is required to rais0tr f t*df2lo4e the temperature of 30.0 kg of water from 15 0 tf42fdl*tro$^{\circ} C$ to 95 $^{\circ} C$ ?    $ \times10^{7 }\,J$

  To what temperature will 7700 J ofuxbv 3,u 0kcdc x/rpp/( 8tpd2 heat raise 3.0 kg of water that is initially at 10./uv p3b 8puxrkc0c(/2x,ddt p0 $^{\circ} C$ ?    $^{\circ} C$

  An average active person con0c7 uov/m,ez 64rlgsm sumes 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 of unitszhs8h zarb06:0 unu+(2 pkalv. One Btu is defined as the heat needed to raise 1 lb of water b 08auspv hln62zr+0uhaz(kb:y 1 F $^{\circ} $ . Show that
1Btu = 0.252kcal=1055J

  A water heater can gedis x p3/r+k1;x*o fxanerate $32,000\,kJ/h$ 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 lysle*-0 5wzdie 1ve8-uld 7 y350 W. Estimate how long it will take to heat a cup of soup (assume this is 25y1d*lwi-ed u70lee-sv8yl z5 0 mL of water) from 20$^{\circ} C$ to 60$^{\circ} C$ .    min

  How many kilocalories are generated when the brake,f(id ezf jvj8*h+ys;s are used to bring a 1200-kg car to rest frof d(y+e,fv*jz i j8;shm a speed of $95\,km/h$ ?    kcal

  An automobile cooling system holds 16 L of water. How muv9ek lzb.umh3 vx47z/s7 p 542yoirfo ch heat does it absorb if its temperature rises fr7li2 p47vz3survxfhobz mk o 9ye 54./om 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 need2l 3;kdn8fhckb kb,u dzm.,-l ed to raisen- bhkz8 2km,cld lk;f,.u3db 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, asqv 4v :ct59 ona5dk8gnd water experience the same temperature rise when they absorb the same amount of heat. What is594ka: qnov8vsdg5 tc the ratio of their masses? [Hint: See Table 14–1.]$m_{Cu}$ : $m_{Al}$ : $m_{H_2O}$ =    :    :   

  A 35-g glass thermometer reads 2( wzl6rs:zdbt*u+d :l1.6$^{\circ} C$ 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 equnolnun,11q-ino0d 3filibrium temperature 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 m qh (jejce0jgbr4 s*1/of2y-cu1*o c(mass = $0.4\,kg$) just forged (Fig. 14–16), is dropped into 1.35 L of water in a 0.30-kg iron pot initially at 20.0$^{\circ} C$ . If the final equilibrium temperature is 25.0$^{\circ} C$, estimate the initial temperature of the hot horseshoe.    $^{\circ} C$

  A 215-g sample of a substance is heated tf e/pk73 r/wfro 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 coff)ftgi u.6t8 preepot to bring to a boil 0.75 L of water initia6f)u 8ritt.pg 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 moll. f) gv+/aof candy from the following measurements. A 15-g sample of the canda fglv.m+/ol)y 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 is 15.0$^{\circ}C $ , and its temperature after ignition is 53.5$^{\circ} C$ .    Cal

  When a 290-g piece owq9 oipgy)gq *jj++(r f iron 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 +o ;z /8 ppsw/iw6r7 kxse:dvcrbq0 h/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 an ob t/ fh/vei l-,u/da:uwject is defined as the amount of heat needed to raise-ld twf//,:v/iauu he its 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 kk)x4zp - kw sc*s7cq+zg of silver that is initially at 20$^{\circ} C$?    $ \times10^{6 }\,J$

  A 0.095-kg aluminium sphere is dropped from the roof of a 45-m-high buildik.nmn8/5uzkmd/uz c *9gri 2zblup;1ng. If 65% of the thermal enzgr kncz5 .mzum*b9/u8 dkinu/2pl 1 ;ergy 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 ofl/1 q- 89qmdcgr grh1 mp9v:kbt8 mp+o heat in 30 min by evaporation of water from the skin. How much water has been lost?trbmg pm:9g189 pq+ hm1oq-/crvld k8    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 containe(,*ll (lsjm0(h wsuiwr of liquid nitrogen. How much nitrogen evaporates if it is at its boiling point of 77 K and has a lat ljh,u(isl*((sw wlm 0ent 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 ai3 y,l*ayi6ss y1gq *ht -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 contah /9 w(pp rgp3nyn3y+au-f4b eins 830 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 bicy)a4aw4q hab0 cclist 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 kcal did the rider use during the ride? (Since the efficiency of the a)40h wac 4qbarider 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 10o wzsn6 wkv y3h*;y2mp02ss1a0$^{\circ} C$ 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 mer v8;6lol r+1gcxh 8q zaf7s3brcury 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 travelish9yc+8 f) gj;em e5ktyl*) bvng 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 ktupf3:3e+- jdj10 b lbrnxb9 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 investigator notes that the 8.2-g leadhg qlu0 1(n k9rkave-8 bullet that was srkvne hluk8-q1g (a 90topped 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 dia0jlx i*pt8 mx5meter 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 7c- 9mwhvi y -*hhzjo5flow by conduction in Example 14–10, assuming that there are strong gusty winds and the external thcm57j -*y -ih 9owzhvemperature is -5$^{\circ} C$   $ \times10^{4 }$ W

  (a) How much power is radiated by a tungste ige nia1* wwk(gt72w9n 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 floi80vsem27 paows by conduction from the blood capillaries beneath mpo7v ia82e0s 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-cm-thic r jpktb:o5ls495vc; -wdo9qek brick wall. Because of a number of 100-W lightbulbs in one rvtr9 pe:4oc j;-l9kodbs5wq 5oom, 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 a block oc59hzxikjo.( v5e ytu *s1(h mf 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 ro*ms0g 4gs(4 b6lvkzw tcgk p)(d of the same length and cross-sectional area are attached end to end (Fig. 14–18). The copper end is placed in a furnace mainttzs g 4)lw0k gvk gp*4csb(m(6ained 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 atxq: /v0 h -4 ld/3kjbi,arss1ej/pwrg which the whole Earth receives energy from/ l s//jh4b,a-rips j0e3wqk g1:dxrv 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 generatebt3ff l 9 35o5c)d c.dehkp3uu 0j.hmjs 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 tec0 5u). f cdbumth5klhjo.39jp33dfemperature between the inner and outer surfaces of the glass?   $^{\circ}C $

  Suppose the insulating qualities of the wall o r7joa1.ht4 uyf a house come mainly from a 4.0-in. layer of brick and an R-19 layer of inso ra7uy1t4h.j ulation, 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 1q rlko ir-/,0rrb io6an air space, Fig. 14–20. (a) Show that the rate ob /ol,0ori6i-r1 rrqkf 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 3b:qo3( q;gr zq9rptoshould it take 11.0 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 contains about 0.20 kg of2 *z8xwphbcg;v -mqsza05f(n 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 wob,5h1ju rp5f2gy xqo:g, cdn.rld’s oceans, estimate the heat liberated when a cube ghoxf: 2 y.dunb5cj5,q, 1prg of ocean water, 1 km on each side, is cooled by 1 K. (Approximate the ocean water as pure water for this estimate.)    $ \times10^{ 15}\,J$

  A 15-g lead bullet is tested by firing it into a fixed block of wood with a mas+a9q4i mpn0 htv0 lqc-qhek()s of 1.05 kg. The block and imbedded bullet together absorb all t 0)tq0ievqnah9p4kh-+ l m(cqhe heat generated. After thermal equilibrium has been reached, the system has a temperature rise measured as 0.020 $C^{\circ} $. Estimate the entering speed of the bullet.    m/s

  (a) Find the total powg*99y qs5h9daqyv q 5/ oju/zfzf3,l aer radiated into space by the Sun, assuming it to be a perfect emitter5 af9 g/q/a9fozdz qjvhs39y5 *ylu, q 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 702 *1sevsok :bi7xndz)-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 rolls off the top of fgdf.x-1d r 7cmr:ad9a cliff and falls a vertical height of 140 m before striking the ground. Estimate the tf1fcd7m 9d dg.r:ax- remperature 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 of water initl eotefde58/ g)m,n1rially at 2/d1), rm eg eot58lnfe0.0$^{\circ} C$. If the final temperature of the water–lead combination is 28.0$^{\circ} C$, what was the initial temperature of the lead ball?    $^{\circ}C $

  A mountain climber wears a goose down jacket 3.5 cm thick with total surfa-p2 uxcln3x jt :;y)wyce area:ju n2;lx)py y-xtwc3 $1.2\,m^2$ 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 a,dkwsur 2ce(1 verage metabolism 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 can6 y3yitc/y2 qba 92wgo be conducted from the interior of the body to the surface. Assume that the thickness of tissue is t yiaq b9o32ygwc62y/ 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 (assumejl -wi;nx /h6v conductivity of air) and area/- lxnv ij6wh; $410\,m^2$ 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 traveling at :tvg9itn. h,c$220\,m/s$ 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 raj):9d+c.*mjgzk xy+km 8pp w odiation from the leaf to calculate how much water must be transpired (evaporated) by*k.8xg+o p cm:yjpdm9kz) wj+ 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. If 4 q0krdeu3mao7ylq+yk0k*9 0x naf6u its initial temperature wax m aa klfuy09ko7ynu qd 6+3k40eqr0*s -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 increasozmcc21;pmzo: j )vp3h :(dkgdt+fs7es 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 baqy6j+t6;gwd r ted fu(j1f3xek5 2rj; p7p;blll at a wall until they are about to drop dupdt +tjj ;j1; e( w;lgb7qff6e2 p5 krrdyx3u6e 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 ef85o p8 pnht/kh 48pksqual 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 conduction and radiation a9 sg;s;aw9 )w +2-fv qr0ic gk+a5wj qmxj2jekt a rate of about 200 W. Estj x g9ijs2 )5jq9rawq ac;vefw;k2 +w-0sk m+gimate how 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 50-gawaqc)zysn) * 6l vwwp i3(g.+sl (185-L) water hep*w q(6 yvz 3cnia.)s)gsww+later. This suggests that the tank has emptied and refilled with water at roughly 10$^{\circ} C$. (a) How much energy does it take to reheat the water to 50$^{\circ} C$? (b) How long would it take if the heater output is 9500 W?    s

  The temperature of the glass surface zzme71vx)s3 hu.bskl7nd d88of 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.    $^{\circ} C$