What happens to the work done when a jar of orang7s 3se bgd535)hrba jge juice is vigorously shaken?

When a hot object warms a cooler object, doesfmz3+vpdv19 f tx qmb6 r/ )t,t:mdl7s temperature flow between them? Are ts):6b ,m/p zv r tdtmtfxl17qvmf93+ dhe temperature changes of the two objects equal?

(a) If two objects of different temperatures are placed in contat j5i;tw97t(wrgfl ,rct, 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 irli(7r;9gt5 jtw , tfwnternal energies of the two objects are the same? Explain.

In warm regions where tropical plants grow but the temperature may drop d1 gwq;px x/ 5vqyjaxn) (jr-*below freezing a few times in the winter, the p-a vq 1*x;yn5j (jg)dr/qxwx destruction of sensitive plants due to freezing can be reduced by watering them in the evening. Explain.

The specific heat of water is quite large. 4bk -5allw4pjj7 8 xkcExplain why this fact makes water particularly good for heating systems (that is,w 57 - jck4kxp8j4allb hot-water radiators).

Why does water in a metal canteen stay co*sq ei+4spp4c oler if the cloth jacket surrounding the canteen is kept moi s *e4s4piqcp+st?

Explain why burns caused bpb9 )k+xkae;h y steam on the skin are often more severe than burns caused by watx9b;eahk+p k)er at 100 $^{\circ} C$ .

Explain why water cools (+kn6 v/e vyvr6ni 0-nvits temperature drops) when it evaporates, using the concepts of latent heat an r6 v/enn vy6v-vki+0nd internal energy.

Will potatoes cook fasterg oj,ys)r+el7z6zr./a zs o6:ns1bkm if the water is boiling faster?

Does an ordinary electric fan cool the air? Why or why not? If nog6 ;3irjx+ yt*t2klk2g mc5,q mc8ibat, why use it?

Very high in the Earth’s atmosphere, the temperature ca(eg+qfax;mlxgm445wu k / vj, n be 700 $^{\circ} C$ . Yet an animal there would freeze to death rather than roast. Explain.

Explorers on failed Arctic expedit e9cb+aut*+ d/kk ell;eylv- 7au;+ qeions have survived by covering themselves with snow. Why would they do thata tle; uvb/l9+e e a7u+yk*ckdqe+l-;?

Why is wet sand at the b3(1nht jbuc lpe;p/ulkx+i 01each cooler to walk on than dry sand?

If you hear that an object has “high heat content,” does that m9f2tssg,g/l4fr/ ye -av *fpaean that its temperature is high? Explafp *s/,4eft-9/sag lv2 yafgrin.

When hot-air furnaces are used to heat h7,u,h/xkaqcl hn+-v a house, why is it important that there be a vent for air to return to the furnacevukhn7/h,x c lh+a, q-? What happens if this vent is blocked by a bookcase?

Ceiling fans are sometimes reversible, so that they drive the air down in ob dm9cgdd-5 7tne season -d cg5bdt7d9m and pull it up in another season. Which way should you set the fan for summer? For winter?

Down sleeping bags and parkas are often specified as so many inches or centimet jfl,27-hrj*gcy9 ak12b hwhi ers of loft,j,9chj *ry2-ihkg 1l72 a hwfb the actual thickness of the garment when it is fluffed up. Explain.

Microprocessor chips have a “heat sink” glued on top that looks like a serfodnb+py8n 8h0 cx j+m6l(+eyies ofy+bhxd(on yj+l mc+6n8pe0 8 f fins. Why is it shaped like that?

Sea breezes are often encountered on sunny days at th /t13m e:w z77prnimzre shore of a large body of water. Explain in light of the fact that the temperature of the land rises more rapidly than that of the n 1z 73zer n/7irmpm:wtearby water.

The floor of a house on a foundation d 49b:sk;t6qy52jhds n 4fdcvtx1 b.q under which the air can flow is often cooler than a floor thatqb.xk42vt t6 bfd dq5:c h sj;94dysn1 rests directly on the ground (such as a concrete slab foundation). Explain.

A 22 $^{\circ} C$ day is warm, while a swimming pool at $22\; ^{\circ}C$ feels cool. Why?

Explain why air temperature readings are always taken with the thermometer innlempho5 fjp+01g/ d a kj,tj0rxr ,8( the shgjh0rl0t1a8 ejpod mk (rpx+,fnj,/ 5ade.

A premature baby in an incubator can be dangerously u; jfto//:sh( ydqv :qcooled even when the air temperatureyuot:;svd/jf(qh q/ : in the incubator is warm. Explain.

Why is the liner of a thermos bottle silvered (Fig. 14–15), and why6( bzz)q b(af,ie- /x wf)v s;*myacuy does it have b()y;bz xi/s6(yf uae qzv -aw*f,c)ma vacuum between its two walls?

Imagine you have a wall that is very well insulated 3 vx:fmkeq8;e tt: +fn— it has a very high thermal resistat fnk e8mft;3x::qv+ ence, $R_1$ 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 the following processes: (1) lp y)+ hoq9)in5 lw1. y m771vquxilsgventilation 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 q. 1wl7)g +ioy9s1)uplmqli7 n yv5hxwhich of these heat losses? Explain in detail.

A piece of wood lying in the Sun absorbst3y4 5ep 7n9xcdmyk n40f4.a cf,nap o more heat than a piece of shiny metal. Yet the wood fe4nop597nfpxc4 m4 3k ,dfa.t0yac eynels less hot than the metal when you pick it up. Explain.

The Earth cools off at night much more quickly whb. sm /pvbz c 7zt twpz-;ig6;i/39lnaen the weather is clear than when clon.tsplb i/6 ci; vz3zw/pgat7- b9m z;udy. Why?

An “emergency blanke 9 uss.72fcecier(f-c t” is a thin shiny (metal coated) plastic foil. Explain how it can help to keep ancsire s79.f -ccfe( 2u immobile person warm.

Explain why cities situated by the ocean tend to have less extreme temp oooe-2dbn q-di f:;/xda3if yt,k* f6eratures than inland cities aty a;f/ib, qt: xodo-dief*okfd-623n the same latitude.

  How much heat (in joules) is required to raise the temperature of he(49bitt,: w4fejbb l(tp0 q 30.0 kg of water froefwbbt(t l4jh p:4 09tei(bq,m 15 $^{\circ} C$ to 95 $^{\circ} C$ ?    $ \times10^{7 }\,J$

  To what temperature will 7700 J of heat 1 mhs szr1qs:x-; u;lhraise 3.0 kg of water that is initially at 10.h xsmzsr- q1: 1hl;us;0 $^{\circ} C$ ?    $^{\circ} C$

  An average active person bie4yogbmzvs,bg 839 h+hzu)8 b9c7w consumes 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 Britij, y1lgih6e(v h m3 srhqsi(3w 4n:4cmsh system of units. One Btu is defined as the heat needed to raise 1 lb of water by 1 F m6h4( :nwr i(13y sghcjvmelih3,q4s$^{\circ} $ . Show that
1Btu = 0.252kcal=1055J

  A water heater can ghxhm b9m:;px1os 35h generate $32,000\,kJ/h$ How much water can it heat from 15 $^{\circ} C$ to 50 $^{\circ} C$ per hour?    kg/h

  A small immersion heater is rated ati3zjegb b(:w+m p3h2kg ,z kj8 350 W. Estimate how long it will take to hea,ij ewj2phbkmk +:3z(gbz 3g8 t a cup of soup (assume this is 250 mL of water) from 20$^{\circ} C$ to 60$^{\circ} C$ .    min

  How many kilocalories are generated when the brakes arlia6q ;vqfs ;+e used to bring a 1200-kg car to rest from qi+;lsa;6fq va speed of $95\,km/h$ ?    kcal

  An automobile cooling system holds 16 L of water. How much heat does it ( *lcc t)fze w4pm.iz4hj,/nsabsorb if its temperature rises froi,.*s(zjmhpl/w ne4c)z t4fc m 20$^{\circ}C $ to 90$^{\circ} C$?    $ \times10^{ 6}\,J$

  What is the specific heat of a metal substance;1ag)agn*uncy7s0(*tz tu vo if 135 kJ of heat is needed to raise 5.1 kg of t7gsg; (t**zvu ntna)oy c1u0 ahe metal from 18.0$^{\circ}C $ to 31.5$^{\circ} C$ ?    $J/kg\cdot\,C^{\circ} $

  Samples of copper, aluminum, and water experien9d -*b pvi.fn p6gz/lg9)x frzce the same temperature rise when they absorb tgdr9)/9blvfx ziz p - f6gp.n*he same amount of heat. What is the ratio of their masses? [Hint: See Table 14–1.]$m_{Cu}$ : $m_{Al}$ : $m_{H_2O}$ =    :    :   

  A 35-g glass thermometer reyebuy :kz)* qk8x k,,tads 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 teifnk5 f2rk/x) mperature 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 (mm16cavv4 z z5mzyzg n/4t2g+pass = $0.4\,kg$) 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 jipol) ).6 s9tvz0(, al (1lddhs erytis 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-W coffeepot to bring to a boil 0.75 L o o0/oi*arpv -rf water initially po*0r rvoi a-/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 af:6d8o rp 4mqcw b( /a9rpu m(46dsyg75 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 contained in an aluminum calorimeter cup of mass 0.624 kg. The initial temperature of thdds bq4:mpaf(8(6gopy4/m 9c r6uawre mixture is 15.0$^{\circ}C $ , and its temperature after ignition is 53.5$^{\circ} C$ .    Cal

  When a 290-g piece of ckt/*j we)sxj,a. on: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 hammer hask fvn*:.x6eya mg+,nwz ges 7, 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 defineqm5 p y4pmj1 9zt:is;4k6o xvxd as the amount of heat needed to raise its temperature bpy9j m:x4;461 iqs 5mt pxovzky 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 ws ci3)z 9t6tron 3ba+8azpk+is initially at 20$^{\circ} C$?    $ \times10^{6 }\,J$

  A 0.095-kg aluminium sphere is dropped from txltz;0u6 swf9 h.c ru*s5rwz:he 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 tempera0l. w :*r6w5u ;csfr tusxhz9zture increase?    $C^{\circ}$

  During exercise, a person may give off 180 kcal of he*ac.0 gamxsrw/ y9qflwy pt54)5cbt /at in 30 min by evaporation of water fr/45amcc r/t. s) y wayxp5b9lgq0w*tfom 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 containeofx/9+zjc8jy+1 b1i*waz tmkr of liquid nitrogen. How much nitrogen evaporates if it is at its boiling point of 77 K and has a latent heat of vaporization oj+z* 9fz+1jm1xykoci wb t8a/ f $200\,kJ/kg$ 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 tak1,-xh/k rv m 8e l0nbusg64yacen from the freezer 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 p 86so.i)je9twltbfi;f1 5:hhhi 7 rxkg contains 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 bicyclpz1z2 v.e3y sy bq9oo*u z/5tiist 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 mtzopz 2 3s.i1/obuvqyy5*ze 9uch energy in kcal did the rider use during the ride? (Since the efficiency of the rider is only about 20%, most of the energy consumed does go to heat, so our approximation is not far off.)    kcal

  What mass of steam at 100*fk-b1h:hqikkj - 6zv$^{\circ} C$ 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 nz8qu,8o5e s bqla )w+mercury is $138\,J/kg$$\cdot\,C$ Determine the latent heat of fusion of mercury using the following calorimeter data: 1.00 kg of solid Hg at its melting point of -3.9$^{\circ} C$ is placed in a 0.620-kg aluminum calorimeter with 0.400 kg of water at 12.80$^{\circ} C$ ; the resulting equilibrium temperature is 5.06$^{\circ} C$ .    $ \times10^{ 4}$ J/kg

  A 70-g bullet travel/ rc7 b.8cgg1jzm5o20m bj.fralf*pming 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 movinj3:-b x9az dob9,xm4.mp bsodg 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 wzt0hf9/1emp+ c( gus lead bullet that was stopped in a doorframe apparently melted completely o/0ehmf 9u1ptsw c(+z gn 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 d)1g4 ijd bxw ye5o.b4jiameter 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 lg2a pn53 486 y9jkyzxf ybwh1by conduction in Example 14–10, assuming that there are strong gusty winds and t5bw9 pj yf26zl1hxk84g3 yn ayhe external temperature is -5$^{\circ} C$   $ \times10^{4 }$ W

  (a) How much power is radiated by a tungsten h9(-u prqlr4p9; vr rgsphere (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 conde lq:dvfy3g 5e2y99ams x*- i 2ffi5rmuction from the blood capillaries beneath the skin to the body’s surface y:2xqm9egs 2m3if5l*efvd-a5 f9yr iarea 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, sharshw,w rxopgsmb4p .j33r:i9w(i 4n :he a 12-cm-thick brick wall. Because of a number of 100-W lightbulbs in one room, the air is atir 9n4om,p p. w:j3:sxghhs4(bwiw 3r 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(ka,.5wld+qzr9tr xnzs it +, Sun 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 aluminum rod of the same length and cross-sectional area are0x5 (8d7silfadxy .w)) moeh v attached end to end (Fig. 14–18). The copper end e.) oxw(5ddh ax ym0iv)lf7s 8is placed in a furnace maintained at a constant temperature of 250$^{\circ} C$. The aluminum end is placed in an ice bath held at constant temperature of 0.0$^{\circ} C$ . Calculate the temperature at the point where the two rods are joined.    $^{\circ} C$

  (a) Using the solar constant, estimate the rate at which the whole Earth rf;z0kb8s zdu:2 s5lh. w nkl:veceives energy zd20v5skwz f:;lusk. hb: ln8 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,* rookioiy o5-lv uk8a4*5yv9 which is dissipated through a glass bulb thkr5i 94yovyo u-5oklo **8ivaat 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 of the glass?   $^{\circ}C $

  Suppose the insulati, gc7sp93wjjs8bp,8c uwgz3 a4pa: wyng qualities of the wall of a house come mainly from a 4.0-in. layer of brick and an R-19 layer of insulation, as shown in Fig. 14g u8ga8, 9 ,spzy:cw 7pcpww3 4jbaj3s–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 panz hjns19x6ua,j jll8 fcuw;3 .es of glass separated by an air space, Fig. 14–20. (a) Show that the rate of heat flow through such a window by conductjac 3hfus ;w.u8691nz j lxjl,ion 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 tas/(tn bnn-y6.0vtxk cg+ vwe/ ke 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 of liqus)mlo f x38u3pg ;kxzf.6p0gyid 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 much9xrtf2 vc5)y v thermal energy is contained in the world’s oceans, estimate the heat liberated when a cube of ocean water, 1 km on each side, is cooled by 1 K. (Approximate the ocean water as pure water for this est)9v t c52yrfxvimate.)    $ \times10^{ 15}\,J$

  A 15-g lead bullet is tested by firing it into a fixed block of wood aong427 sm7h(o- pyl lwith a mass of 1.05 kg. The om7py42-gahn(l7 losblock and imbedded bullet together absorb all the 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 powerwc 70ficxiv53ro*. ku radiated into space by the Sun, assuming it to be a perfect emitter at i5fcow.x7i*vr0 ck3 u$T\,=\,5500K$ 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 m40u8tqzd 20znyys)z1wo byd2ay 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 thejnln1oxvd-7 92s63. e zl f:fgqprr i;/mg0mr top of a cliff and falls a vertical height of 140 m before striking the ground. Estimate the temperature rise of the rock if 50% of the heat generated rd- ov1 mrs/ ;j.zx920rlnif3 l:gp6fm7e qg nremains in the rock.    $C^{\circ} $

  A 2.3-kg lead ball is droppedv toy7z80d *k poac2ux-j*wqf; c dz)4 into a 2.5-L insulated pail of water initially at 2yozt *8pku2dad-wxo 0;jz *c q4)v7c f0.0$^{\circ} C$. 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 w+)jig s 1a5armwjkghfi( gg:xh 79x8 ;f;gm 0xears a goose down jacket 3.5 cm thick with total surface are(x mm)i i9xsk7hgjg ; xahwf g5a0 g:+1;fjgr8a $1.2\,m^2$ 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 averageo. zzfx) 4ehu;c zqd6) 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 can be condsga l76u z)u8oe 5ed*gucted from the interior of the body to the surface. Adoz)7la 5 see u*8gu6gssume 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 conductivity of air) andxtt.v qgk;w8 : ar wqkt:8xv;g t.ea $410\,m^2$ a roof of wood 6.5 cm thick and area $280\,m^2$ and uncovered windows 0.65 cm thick and total area $33\,m^2$
(a) Assuming that heat is lost only by conduction, calculate the rate at which heat must be supplied to this house to maintain its inside temperature at 23$^{\circ}C $ if the outside temperature is -10$^{\circ} C$    $ \times10^{5 }$W
(b) If the house is initially at 10$^{\circ} C$, estimate how much heat must be supplied to raise the temperature to 23$^{\circ} C$ within 30 min. Assume that only the air needs to be heated and that its volume is $750\,m^3$    $ \times10^{ 8}$J
(c) If natural gas costs 0.080 dollars per kilogram and its heat of combustion is $ 5.4\times10^{7 }\,J/kg$ how much is the monthly cost to maintain the house as in part (a) for 24 h each day, assuming 90% of the heat produced is used to heat the house? Take the specific heat of air to be $0.24\,kcal/kg$$\cdot\,C$.    dollars

  A 15-g lead bullet try,zs(ml nog8n be8 g20aveling 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*y w68lz6b: ev.g9pxyir0wzs, take into account radiation from the leaf to calculate how much water must be transpired (evaporated) by the leaf per hour to maintain a temperaturw6 :68blr yv.yixe9w0sg *pzz e of 35$^{\circ} C$.    g/h

  An iron meteorite melts when it enters the Earth’s atmosphere. If its inn9w4e2o-az30uklhkc /xxxol; )s i ;sitial temperatu2lz)4ooxhnl39/sk xai xuk ;c0ews-;re 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 inkm;-sp9a,w rh+mmoo w,d 8xh4creases 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 sof( k v6igm/fevrhzd1 6 9ohq w*bz9*1tft rubber ball at a wall until they are about to drop due to dehytf(9z*1 619bkh h 6v*oiw /v zgqrdemfdration 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: p5n0g1pl :8twoyn fs equal masses of ice at 0$^{\circ} C$ and steam at 100$^{\circ}C $ are mixed together?

  In a cold environment, a person can lose heat by conduction and rac:d j2zv4hboc.eh t ))diation at a rate of about 200 W. Estimate how long it would take 4jvh)e:zbh2).dt cocfor 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, thexs ad6:9o ln0sxbzan(1f *qq t4x72co7tj5n bre is “no hot water” left in the 50-gal (185-L) water heater. This suggests tha4x0anln (9bbz 1xo*5fxs6att:sjq c7o 2 7nqdt 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 4 r1u3 4(r th)4yc8w3nqyqbp :gsrdxq/z o ws;glass surface 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.    $^{\circ} C$