What happens to the work done when a jar of orange juice is vd+-2yxrdu,n + oybxtq6 6i t0kigorously shaken?

When a hot object warm,pt8 nl fd v3n(f39j5pk/uzzws a cooler object, does temperature flow between them? Are flpnf3 9 z5pz,uwtd (j3nk8/vthe temperature changes of the two objects equal?

(a) If two objects of different temperatures are placed in contact, will +pckdtup( +.n: u a,dov3i5ch heat naturally flow from the object with higher internal enhaukpd vdc3oiu+.:5pt(, nc +ergy 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? Explain.

In warm regions where tropical plants grow but the temperature may droq pq8eai4y of 47*r(gtp below freezing a few times in the winter, the destructionqayp74qei 4r8(* ogft of sensitive 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 water parr7wdfg9o i,oub 640llticularly good for heating syste wd0u67lgo9lo4r, bifms (that is, hot-water radiators).

Why does water in a metal canteen svqk ,c;lcc i10:c11jzlxzw0 etay cooler if the cloth jacket surrounding the canteen is kepte:wk,iq1 z0 0;c1xlcljzvcc1 moist?

Explain why burns caused by steam on the skin are often more severe than bu4(lv igg21nw n mjcy34rns caused by wayg4n4 1 iw3vcln( m2jgter at 100 $^{\circ} C$ .

Explain why water cooladrj.nb+qbr*x2y*hb53 g9 r os (its temperature drops) when it evaporates, using the concepts of latent he +3gxqbdb5nryh .9o j2 **rrbaat and internal energy.

Will potatoes cook fa( ,sjaggh.7ybe oe(yo m*a44g ster if the water is boiling faster?

Does an ordinary electric fan cool hd 8 (3 n7sd0qa+yu9oc m5lsvvthe air? Why or why not? If not, why use it?

Very high in the Earth’s atmosphere, the tx 0jd /-lxy1nq:pdl5h emperature can be 700 $^{\circ} C$ . Yet an animal there would freeze to death rather than roast. Explain.

Explorers on failed Arcgx4t;5bx qi y-tic expeditions have survived by covering themselves with snow. W4- xg tbq;i5xyhy would they do that?

Why is wet sand at t h;8b.q0 n0 i3bmw ;vulnnz+rthe beach cooler to walk on than dry sand?

If you hear that an object has “high heat content,” does that mean tjogg hx gm(1,x 45)rxwhat its temperature is high? Explaih r,4()1g wjxxo ggm5xn.

When hot-air furnaces are used to heat a o.bf1m)jj u c0;zzg t.house, why is it important that there be a vent for air to return to the furnace? What happens if this.; )zbuc1.gjfoj0 t zm vent is blocked by a bookcase?

Ceiling fans are sometimes reversible, so that they drive the air down in one sew4n3om5aj8k 4x39eam 7gfy9o.xai nqason and pull it up in another season. Which way shoua 5mg4ki3naoye79jn8xoqmx. 3a w f94ld you set the fan for summer? For winter?

Down sleeping bags and parkaafsud9sx;m-a qzd, 4(s are often specified as so many inches or centimeter(ad9 a usd;4-mzsq,xfs of loft, the actual thickness of the garment when it is fluffed up. Explain.

Microprocessor chips have a “heat sink” glued on top that looks like itq wk1whp.h1i 0vkxf7n2dpk,45wj,a series of fins. Why is it shaped like khq,h1i17,i4 .2t k p0w5 xkfww nvjdpthat?

Sea breezes are often encountered on sunn4mcq , ivurd1s.*me d0y days at the shore of a large body of water. Explain in light of the fact that the temperature of the *m0 41re dvi.scdq ,muland rises more rapidly than that of the nearby water.

The floor of a house on a foundation under which the air can flow is often coolfwlw(*i:u gql6x6a1 hdo-vsvk- ax93er than a floor that rests directly on the ground (such as a concrete slab foundation). E v*q- l oxx1wf-6ivdkg whaa3u:(69slxplain.

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

Explain why air temperature readingsvu01 opjq ao9 ,w2o3zh are always taken with the thermometer in theoa3u w0pj1 o2vqz, ho9 shade.

A premature baby in a fjs+mnd+ r01in incubator can be dangerously cooled even when the air temperature in the incubator is warm. ++d01jmir nfsExplain.

Why is the liner of a thermos bottle silvered (Fig. 14–15), and wheffg6l*wcpnx.5 .u + ,0incuby does it have a v ex6igpcw l .nnu*5u,b0+fc.f acuum between its two walls?

Imagine you have a wall that is very well insulated — it has a vd i0f pe13ta(3nhx;lwery high thermal resisfl3pi ew (a1 th;3nx0dtance, $R_1$ 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) c8lev2f9(by(i qmm abd(:of:9 p bw-yventilation around edges; (2) through the frame, particularly if it is metal; (3) through the glass panes; and (4) radiation. (a) For the first threm(fypo(-lq8 bi ( ewmc:vda :2 9bf9ybe, 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 more hea .akm/a0k hrz 8rg-fr6t than a piece of shiny metal. Yet the wood feels less hot than the metal when you pick it up. Erma z .8khrg60/fa-rk xplain.

The Earth cools off at night much more quickly when the weather is clear than whf9qo/d:rfm+ r enr+:9r /m dfofq cloudy. Why?

An “emergency blanket” is a thin shiny (metal coated) plastic foh *y,nhlm brzgjo:r/a*5-u,m* tz1tl il. Explain how it can help to keep an immobile perhbzr ,/lz* m :l-y5un*otta gr j*m,1hson warm.

Explain why cities situated by the ocean tend to have less extreme te c(4budw9v4 vrmperatures than inland cities at the same rb44 dcvw(v9ulatitude.

  How much heat (in joules) is required to raise the temperature of 30.0 kg of wah b)f2;iqv5cjter fro;c b2 hjqfi)v5m 15 $^{\circ} C$ to 95 $^{\circ} C$ ?    $ \times10^{7 }\,J$

  To what temperature will1r;vi ;xb gex9 7700 J of heat raise 3.0 kg of water that is initially at 19re;gixbv; 1 x0.0 $^{\circ} C$ ?    $^{\circ} C$

  An average active person c q-v*x m2djz7rt;a83kfelb ,honsumes 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 un h1chf00e:nw xit (Btu) is a unit of heat in the British system of units. One Btu is defined as the heat needed to raise 1 lb of wate10hnw:xef0 c hr by 1 F $^{\circ} $ . Show that
1Btu = 0.252kcal=1055J

  A water heater can gend, 9e)nnrr 4zh4)og,w2aedptmu z-(m erate $32,000\,kJ/h$ How much water can it heat from 15 $^{\circ} C$ to 50 $^{\circ} C$ per hour?    kg/h

  A small immersion heater is rated at 350 W. Estimate how long itdry5qcv54r:8g pf v. w will take to heat a cup of soup (assume this is 250 mL of water)4w 5 v8 r.:pvrdg5cfyq from 20$^{\circ} C$ to 60$^{\circ} C$ .    min

  How many kilocalories are generated when the brakes arem oynxty5i:( 6*mvzj:d:e3:idhs1o j used to bring a 1200-kg car to rest from a speed of oditmsjzie:5j:xm3n (1o*6y:vhyd :$95\,km/h$ ?    kcal

  An automobile cooling system holds 13yp3x6y yb r2n6 L of water. How much heat does it absorb if its temperaty xn2 3y3y6brpure rises from 20$^{\circ}C $ to 90$^{\circ} C$?    $ \times10^{ 6}\,J$

  What is the specific heat of a metal substance if 1:,.f oay 4o7y5 twd6azfgv k p8fs2ha835 kJ of heat is needed to raise 5.1 kg of the metal from ,p.z2yf h8gs: k4ofdva6 o 7 85ayaftw18.0$^{\circ}C $ to 31.5$^{\circ} C$ ?    $J/kg\cdot\,C^{\circ} $

  Samples of copper, aluminum, and water experienc vn5tq -2n:p6uhj*n nrg8dfk7 e the same temperature rise when5t8kfpn62nq-gn 7dr*:j uvnh they absorb the 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 reaebb2 gd.3f tn.fbl gxk +hrye, 4f(t64,ap4izds 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 tempera s3pbkkl6g 35ature 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 (mus) 9,b op c0dc/qhdf)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 substancedi/g +z0sd:k) eoj;ldx*y/ev nsi )(c is heated to 330$^{\circ} C$ and then plunged into a 105-g aluminum calorimeter cup containing 165 g of water and a 17-g glass thermometer at 12.5$^{\circ} C$ . The final temperature is 35.0$^{\circ} C$ . What is the specific heat of the substance? (Assume no water boils away.)    $J/kg \cdot C^{\circ} $

  How long does it take a 750-W sz0:c pwi/lt 8 d90omxcoffeepot to bring to a boil 0.75 L of water initially t o8m:xc0 dp9 /zsl0wiat 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 measurements. 5p tkk5vkemx 0ir,): oA 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 ivx0 :k ktker om5,p)5of 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 5kwo xpv p//kxz,/l 4e180$^{\circ} C$ 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 has18zg 7icq )sb om,u7hqa(zh/y a speed of $6.5\,m/s$ just before it strikes a nail (Fig. 14–17) and is brought to rest. Estimate the temperature rise of a 14-g iron nail generated by 10 such hammer blows done in quick succession. Assume the nail absorbs all the energy.    $C^{\circ} $

  The heat capacity, C, of an object is defined as the amount of hea)evv0,re;s jg h(qp,zt needed to raise its temperateh,ge ),qjsrp;(v vz0ure 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 si 5yhvvqs6ua/m yg-7;yw)qtf8ttw/9p lver that is initially at 20$^{\circ} C$?    $ \times10^{6 }\,J$

  A 0.095-kg aluminium sphere is dropped from the roos5 a7r 0c)t2 jxr(+gwu5scoxy f of a 45-m-high building. If 65% of the thermal energy produced when it y5j2o+x7ta)s 05 c ucgrswx(r 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-cjz m83 1ze,aw-x qkl heat in 30 min by evaporation of water from the skin. How much 3e1 z,wmakjczl -qx8- 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 m)+r6hnalc0sac-b x; ;rp1 dvinto an insulated container of liquid nitrogen. How much nitrogen ecc )lrv; ards-m+ hn1x b;a0p6vaporates 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 -smd+m+hv3o6emp 7ux9:d t2 oz8.5 $^{\circ} C$ and placed in a 95-g aluminum calorimeter filled with 310 g of water at room temperature of 20.0$^{\circ} C$. The final situation is observed to be all water at 17.0$^{\circ} C$. What was the mass of the ice cube?    $ \times10^{-3 }$ kg

  An iron boiler of mass 230 kg contains 830 kg oflq9alp a4g+:gvie k 1i.6mah* 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 bicyclist consumes 8.0 L of k6qe2i f7vnh: water over the span of four hours. Making the approximation that all of the cyclist’s energy goes into evaporating this wate2:niq e kfhv67r as sweat, how much 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 1 a fcwidc3zas,t2)0 t100$^{\circ} C$ 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 * 9by wfrfl.h3mercury 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 travelingoj,e)2 svyfgb7j6r z7 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,b84 c gct6ep (ut+8iagstm 86s-z ixi 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 j ,7ljrr.u n4,+kf5qm:wv:z s j2l,f7ajeapilead bullet that was stopped in a doorframe apparently melted completely on impact. Assuming the bullej7z,j ,kl+e:.qjas r7 j iv5nupf4m r:2,fl wat 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 q-x7:trz tg..g(vr2+awmooy: r o5wj 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 conduc4s2ym kzi 6f6ction in Example 14–10, assuming that there arez6ik4 f2my6cs strong gusty winds and the external temperature is -5$^{\circ} C$   $ \times10^{4 }$ W

  (a) How much power is radiated by a tungsten sphere (emissivitr 3k es vl(ef:tgg(r:5y $e\,=\,0.35$) 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 conduction from kkpmb2x0/ nob)1/0 px(o t z:+cv*asdqhz t+i the blood capillaries beneatomdz:2 k)x/(0n1q / +xbsp o+ahk vb*pi0cztt h 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-cl3+sahvo weg ,tgw1w) bi;m k, -u:3rsb.nu; cm-thick brick wall. Because of a n: -enwg.avg ,tw; lcuksru);o3+bbs1,3wi mh umber of 100-W lightbulbs in one room, 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 tol 4us5u*4x 3lpht2as i 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 lengty-qa,jgx 5qbwgvhb8/8qst5gnt , 1q )h and cross-sectional area are attached end to end (Fig. 14–18). The copper end is placed in a 88x /g yswnqqb5h)qtqtb,,vg51a- g jfurnace 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, 5oexwh 6bt kl,g+:zs5estimate the rate at which the whole Earth receives,zt6kb5 l5hw x:o esg+ energy from the Sun.    $ \times10^{17 }$W
(b) Assume the Earth radiates an equal amount back into space (that is, the Earth is in equilibrium). Then, assuming the Earth is a perfect emitter ($e\,=\,1.0$) estimate its average surface temperature.    $^{\circ} C$

  A 100-W lightbulb generates 95 W of heat, which is dissipated through a gl+sf:pr,i -l uaass 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 outi:,s-al+ufp r er surfaces of the glass?   $^{\circ}C $

  Suppose the insulating qualities of the wall of a house come mainly fromr8we ty f4g w**jv8dc0 a 4.0-in. layer of brick and an R-19 layer of insulation, as shown 8y w 04g*jrdtvcewf*8in 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 an air space, Fig. 1y awzoj-i/h3i.d yl3zv-(9b c4–20. (a) Show that the rate of heat flow through such a window by conduction is giv 3dl9(a-b 3wzzioijc/-yhv. yen 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 shou5mlj s(tn(t8lqsf- 2old 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 bfzlem1p)b5r(o k.(s2b mx6 akg 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 oo6v * su/.;*hquszig* (nl ifg1c em0yceans, 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 esu *go1l/s *eicsfyh0v ;.umzi (nq*6gtimate.)    $ \times10^{ 15}\,J$

  A 15-g lead bullet is tested by firqz)n2 gbg705 ygunbn ;ing 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, 7b5by qngzng0 )g;nu2the 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 Sun, assumi w ait +2gp)di6jjl/sf8t3n8 ing it to be a perfect tpwj/8i )jitais8 +g fd3l2n6emitter 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 )ur kv(kd4c8invm0hko; p- fo3+ng /rv,wu2q 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 the8dvs 7. kc(ytb top of a cliff and falls a vertical height of yv.d(8kb7c st 140 m before striking the ground. Estimate the temperature rise of the rock if 50% of the heat generated remains in the rock.    $C^{\circ} $

  A 2.3-kg lead ball is dropped into a 2.5-L insulated pail of wateo0yd( 6( pbbger initially at 20.06e0 (oydbpg(b $^{\circ} C$. 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 hrxwwgw3*zi+;2 9on gwith total surface area3z;x*w 2ggriw 9o w+hn $1.2\,m^2$ 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 i/ w7gxbc/u,v average 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 conducted from the interior o*z) zus-4 nyfcf the body to the surface. Assume that the thickness of tissue is 4.0 cm, that the skin is atcz)zf* 4ny-us 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-insulai w.rxiual+i7o-4f v+ted walls 17.5 cm thick (assume conductivity of air) and area f+a7 ivw4 r+lu-i io.x$410\,m^2$ 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 de 11t/vsi*:3lm *hx femp*slat $220\,m/s$ 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) xb65e8fn5alm y co/c4in Problem 58, take into account radiation from the leaf to calculate how much water must be transym5xeco nf5bac/ 4l68 pired (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. If3mcab:ww rvuf: )jk; - its initial temperature wasbajwmkw:- fu c;:v) r3 -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 withils0 ib*ia2 4hwn the Earth’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 (Fpn l)dk wvvpec3zs6(/(p m 7/rig. 14–22), two people hit a soft rubber ball at a wall until they are about to drop due to dehydration and exhaustion. Assume that the ball hits the wall at a vel/)z7snpd (vl r6/ew(pk3pmcvocity 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 masur7 qamz :7 t/a4cdxk*ses 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 fcs/ p w6l9of6nh*p0 vat a rate of about 200 Wp6 s*lvhcfn9fo60p w/ . Estimate 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 wam1lftf ;8otx08i 5 m-yadnix8ter” left in the 50-gal (185-L) waterimo-y ltmfx15 i;at8880 df xn heater. 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 surfa081e vpvbn 7xjce 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.    $^{\circ} C$