What happens to the work done when a jar of orange juice3 u. borb32mn:k3fq.x cer+x ra1vw+v is vigorously shaken?

When a hot object warms a cooler2 sh))7rb/rsw2mu5 pup pe 3pn object, does temperature flow between them? Are the temperature changes of the two object seu3/7m)nw)p 5p22rhbusp pr s equal?

(a) If two objects of different temperatures are pla p m7l+3ng5kz*t3fq/nn, agsbced in contact, will heat naturally flow from the object with higher internal energy to the object with lower internal energy? (b) Is it possible forgk*+nnt/fqbp5 znlgs m 3a37, heat to flow even if the internal energies of the two objects are the same? Explain.

In warm regions where t rowx* gex76p-cn* bc(i4x wn1ropical 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 e7x*onrx* i cw1bg -n(p6 cxew4vening. Explain.

The specific heat of water is quite large. Explain why this fact ma-:mvmu/tj fqjd:ed+w8 ;y iyiu:*7 frkes water particularly good for heating systrfq /:t i m:dme:;yf+7iyjv-uuw8*djems (that is, hot-water radiators).

Why does water in a metal canteen stay cooler if the clcahp mp* ::nz32y6 uqnoth jacket surrounding the canteen is kept mon2yqmhp :p36zu*nc : aist?

Explain why burns caused by steam on(xj.rp vs5e 3r the skin are often more severe than burns caused by wate r.(rex35sv jpr at 100 $^{\circ} C$ .

Explain why water cools (its temperature drops) when it evaporoc;m+2 6bwi7fl bmk93j m,cmcates, using the concepts of latent heajkm3l c fcm obw;79+ c2bmmi,6t and internal energy.

Will potatoes cook fa 3-yz7g :i 4fby9br,jug 6whphz3,oqmw7su /mster if the water is boiling faster?

Does an ordinary electric fan cool the air? Why or why a 1fi*fbo.i54x-1ousrtmty 9not? If not, why use it?

Very high in the Earth’s atmosphere, the temperature canbt,jk8 z 8 ae*zy:l:an be 700 $^{\circ} C$ . Yet an animal there would freeze to death rather than roast. Explain.

Explorers on failed Arctic expeditions have survived by cover( a aws c99sy1t7mx10y8r2* fqjfyh xzing themselves with snow.(try9hjxsa7 * 8sq0f ay1y 1fwz9mc2x Why would they do that?

Why is wet sand at thma /thxp y23a1e beach cooler to walk on than dry sand?

If you hear that an object has “high hs(m( ivihg.n d-wa+3z eat content,” does that mean that its temperature is high? Explainds whi-(3g am.nv+i( z.

When hot-air furnaces are used to heat a house, why is it importannej+f;we :eu7h n2u2bk2mh)q t that there be a vent for air to rehuu;7 jkeh22m:)wn+e2qf bneturn to the furnace? What happens if this vent is blocked by a bookcase?

Ceiling fans are sometimes 4 fz,8iv(8ezvg6xoarpax9( ayn.sj )dmx/4qreversible, so that they drive the air down in one season and pull it up inm znr)98/ezj( ay x,g(av6 adxf4is4o xv.q8p 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 centimetj alb: x:dct7;ers of loft, the actt:ja; b:l xdc7ual thickness of the garment when it is fluffed up. Explain.

Microprocessor chips have a “heat sink” glued on top (8uuwv5: v ;mzrx a,cvq9mk50ee )cv rthat looks like a series of fins. Why is it shape8, c :xz mc);akmreuq5uw59v(r v ve0vd like that?

Sea breezes are often encountered on sunny days at the shore of a largelfv )s mw ,-p6u*yc.uq body of water. Explain in light of the fact that the temperature of the land rises more rapidly than that of the nearby waterq ,l vp*-s6yfuu.wm)c.

The floor of a house on a fo79gyo:r m1 pm1/xtmm2ihl4pf undation under which the air can flow is often cooler than a floor that r l1phfxom1pg2 yi7:mt/m4 m9rests 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 temperat3)et7g xcif vwdjaiw)x9 +0 4wure readings are always taken with the thermometer in the sha))twga9ef4 7+d 0wcxjiwi3xv de.

A premature baby in an incubator can be dangerously8d 9dx chs.x3i cooled even when the air temperature in the incubator is warm. Expl.cixdh98 dsx3ain.

Why is the liner of a thermos bottle silvered (Fig. 14–15), and why dgp --3nakzd rz+ yeqva+5x3g6oes it have a vacuum betweeznay+pga3q v+ kzx- gr3 e5-6dn its two walls?

Imagine you have a wall that is very wel8lhw+ slcbz (v stcpl743gt7* l insulated — it has a very high thermalblscg*twlv7zh84lc 3s t +p (7 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 windowsf+as3 ny1hph( by the following processes: (1) ventilation around edges; (2) through the frame, particularly if it is metal; (3) through the glass panes; and (4) radiation. (a) For the first three, what is (are) the mechanism(s): conduction, convecthynahfs( +31 pion, or radiation? (b) Heavy curtains reduce which of these heat losses? Explain in detail.

A piece of wood lying in th4m5h d lrh9.8-w1jbtmgrx42:avue an+jjag 3e Sun absorbs more heat than a piece of shiny metal. Yet the wood feels less hot than the metal when you pick itl ng 2mta-meudjxgj:h5j3 w ar9.r+ah4v 14b8 up. Explain.

The Earth cools off at night much more quickly when the weathkbo4m- f5ni 3rer is clear than when -ifrnm34 obk5cloudy. Why?

An “emergency blanket” is a thin shiny (metal coated) plastic foil. Explain how s j*) mc4,zpo;jydbs (it c ,)b smo4pj;szc*dyj (an help to keep an immobile person warm.

Explain why cities situated by the o 3;uya ylom.)h9i uzq4cean tend to have less extreme temperatures than inland cities at the )m.4i 3 oayqzhulu;9ysame latitude.

  How much heat (in joules) is required to raise the temperature of 30.0 kg of wata2i vd/d 4ze-ng1n5ot e2td/ 4 niz1og -adn5evr from 15 $^{\circ} C$ to 95 $^{\circ} C$ ?    $ \times10^{7 }\,J$

  To what temperature will 7700 J of heat rai+my piac ,sr2u1n++fq b;br3 nf, yuw3se 3.0 kg of water that is initially ab+3,qyw f3n+,y2cp;r1+ b ufun sira mt 10.0 $^{\circ} C$ ?    $^{\circ} C$

  An average active person consumes about 2500 Calh (,-hjui5 oai 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 Britis/ql 0g b,cn7cfpa,(elh system of units. One Btu is defined as the heat needed to raise 1 lb of water 0,gn el bcl(aq,f7 cp/by 1 F $^{\circ} $ . Show that
1Btu = 0.252kcal=1055J

  A water heater can generwz 9n:yuxg*45jf h kro84-h frate $32,000\,kJ/h$ 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. Estimatq jhey ocv 4zrly23u)91z*p+oe how long it will take to heat a cup of soup (assume this is 250 mL of water)qvco )hz* pzy4+luo32je9y1r from 20$^{\circ} C$ to 60$^{\circ} C$ .    min

  How many kilocalories are generated when the brakes are: *d.jte 4kdjwp.h/k .jn a)gi used to bring a 1200-kg car to rest from a sh)4jp dajew t.:kg kd/ji*n.. peed of $95\,km/h$ ?    kcal

  An automobile cooling system holds 16 L of water. How much heat does itlog;6 fbl+k8o absorb if its temperature rises from 2of;6ll kbg8o+ 0$^{\circ}C $ to 90$^{\circ} C$?    $ \times10^{ 6}\,J$

  What is the specific heat of a metal szl6ylrt;zl.rxt b( -2ql0f- bubstance if 135 kJ of heat is needed to raise 5.1 kg of the me2 ;y(rr6tlz0b xfz lbqll- .-ttal from 18.0$^{\circ}C $ to 31.5$^{\circ} C$ ?    $J/kg\cdot\,C^{\circ} $

  Samples of copper, aluminum, and water experience the same temperature ri q3hy3balolq6:brz3 i:r 1o s-se when they absorb the same amount of heat. What3h: blsrzar 1:b3qlyoi 6-o3q is the ratio of their masses? [Hint: See Table 14–1.]$m_{Cu}$ : $m_{Al}$ : $m_{H_2O}$ =    :    :   

  A 35-g glass thermometer read qdxlyluui wbmr5a//22ff : 0.pcs+j3s 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 when a 245-g block of cox e8v kmz6q8os:et 7vqy/ 8;azpper 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 (masshv9 zd /dvge0x)td)ro v .xnhg91. r-x = $0.4\,kg$) 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 substanmd+k- 8so zis/w.h3n og6odm3ce 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 2 -v5em v-y*b.jk fbhfa 750-W coffeepot to bring to a boil 0.75 L of water initially at 8bmhff-vy eb5. -k*2j v.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,huitb /3hsy 7 the following measurements. A 15-g sample of the candy is allowed to dry before putting it in a bomb calorimh 7s,hbiu/yt3eter. 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 of iron adp6yc xoy8d/f/, t .pnt 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 has a sx6u*z:wdq+dwc(m a48 hj audzz b9v4sb* 8 tu9peed 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 g- osvz+k h- od,60h+qf/j phz2i-ukd as the amount of heat needed to raisz gvodkpqdj+s/ku hh6+2-fo-, z0i-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 kg of silver that is initially aud+cv5 6wic /4qxjpl;t 20$^{\circ} C$?    $ \times10^{6 }\,J$

  A 0.095-kg aluminium sphere is dropped from the rxe.y y+xr3m3zg:,t6u x tp eo7zn: :jroof of a 45-m-high building. If 65% oxj, :3x:m netr.:z+ eyy3z 7xp6 rgtuof the thermal energy produced when it hits the ground is absorbed by the sphere, what is its temperature increase?    $C^{\circ}$

  During exercise, a person may give off 180 kcal of heat in 30 min by evap*pu l h 2f .rtfa0/jmj-velu2:oration of water from the skin. How much water hatfvua h0:2u* ll- / f2rjjpem.s 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 container of 5o ld07*uyv:a p e;xmgliquid nitrogen. How much nitrogen evaporates if it is at its boiling point of 77 K and has a latent hedm5;a0u eg7xy:l* p ovat 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* mkx h3sh.dwnt bve;m50l39s 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 kg c2)/4cn9 ox 3 gy)o+mehxvxkfrontains 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 bicyclist consumes 8.0r : 9enz4nb3bhj( en(k 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 kc :(9bb nnz(4rn3hek ejal 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 1g/af (dj9)vo w00$^{\circ} C$ 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 merc/t5 2b+ljty eo/r; hprury 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 travelin xdwgn)3,t2qdrf8ag8g 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 at kcv 1td8; rk,/oqp (0f: u*ozlenwbd0$6.4\,m/s$ 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 lead bulle l:(ikz ys:,u/cfk 4kk,dpu 3gt that was stopped in a doorframe apparently m:kkf,c,lupk uz (s d k:i43/ygelted completely on impact. Assuming the bullet was fired at room temperature (20$^{\circ} C$ ), what does the investigator calculate as the minimum muzzle velocity of the gun?    m/s

  One end of a 33-cm-long aluminum rod with a diameter of 2.0 cm is kept js ) ee+66jiq kg7sp;gat 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 conduction in Example 14nmcrrf)*p b8tgw;t5 9–10, assuming that there are strong gusty windstr wrfcg 5;b9mp 8*t)n and the external temperature is -5$^{\circ} C$   $ \times10^{4 }$ W

  (a) How much power is radiated by a tungsten sphere (.qubl *qrdxo ji +0j 9qyp3.*fc*1cqj 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 yhka;71d 7f,n jbse x8sb xk*,conduction from the blood capillaries beneath the skin to thbx ;k8 nkf771xs*eshajydb,, e 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 p yay v;imn +bnrm17+:4.0 m per side, share a 12-cm-thick brick wall. Because of a number of 100-W light;+iv 7r+bmyp 1y:anmnbulbs 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 Sundar21d/ nrdg-s mn.m, 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 crostfkl9 )+vswc0h/5 bqgnmu2c -a 0v pi29mel4 ks-sectional area are attached end to end (Fig. 14–18). The copper end is placed in a furnace buk4c2ispc ek9g 2lm)90qalv vmw50/nt -h f+ 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 Eart)ocq+ hsq9l/wh lk3 ccpqdx6 2. dk9b7h receiveswp/b. s q+c k x)d9c697ckql3h o2dlqh 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 t zyp w8e5tq7j7hrough a glass bulb that has a rw p7 ztje5yq87adius 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 insulating qualities of the wall of w3fz*o ,dej)9bd(etv)bikp- 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 rat dbv*ze)ifd-ow 9(kjp,eb3 t)e 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, Figp/ 9,de4kgwsia +bv fo5 na/k.. 14–20. (a) Show that the rate of heat flow through such iskk d nav5pge/f4b w,+a/o9. 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 takpv)14w;okh,aag fas 0e 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 liquid at 02 dfwxmj 2)yf5$^{\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 hojb2o m 3s8 x3,isrbmdacy:0i5j :iu(jw much thermal energy is contained in the world’s oceans, estimate the heat liberated when a cube yd0ijs xsu, rm:jbb5c3 8jami 2(3oi: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 testedth:x64uc0o c 3ius4v c by firing it into a fixed block of wood with a mass of 1.05 kg. The v3cui6 :x t04scou ch4block 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 power radiated into space by the Sun, assumize k75 (v-uoving it to be a perfect emitter ok( 5evvz-u7i 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- jvfu 0:77w sql8bhq6ekg 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 op-nv2n b,kdq 4y odeg*.r7jdsw6r.z9f a cliff and falls a vertical height of 140 m before striking the ground. Estimate the temperature *k .,qnv pd4sgez.nrybjod 6d2rw-79 rise of the rock if 50% of the heat generated remains in the rock.    $C^{\circ} $

  A 2.3-kg lead ball isfs2rre:n e (hmd )ws,- dropped into a 2.5-L insulated pail of water initially at 2fsed:(wrms)n,e r 2 -h0.0$^{\circ} C$. 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 xxc8lrga8gw 08a7 5xpthick with total surface areaxaxg x8lpag08w78r5 c $1.2\,m^2$ 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 rate of abou7fz f vc50r. rou42gxdt $950\,kcal/h$ 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 int -*tf3y dupcbvnf+gs xfb2( 6,erior of the body to the surface. Assume tha6u3f* f+b-p(2 ngbdx,cv yfstt 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 a*nc *kb7 w7sjr 82jfrcir) and area r 2* 8jcf*7nbc rkjw7s$410\,m^2$ 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 travelingwzw3: p c )f:y ekj sy5gjshb a8ap9k.*pl*o+1 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,oq q:)mpzc2 nsh6 k4 ociv( zi+r7aw/5 take into account radiation from the leaf to calculate how much water mu:o4mcow6 qk+qz ha/ n7i izs(2 r)5vcpst be transpired (evaporated) by the leaf per hour to maintain a temperature of 35$^{\circ} C$.    g/h

  An iron meteorite mel bcj8m0j;: cytu q2do:ts when it enters the Earth’s atmosphere. If its initial temperature was -125 :juotj;b:8cdqy m2c 0$^{\circ} C$ 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 increases 8 btch 2kk/kr4about 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 bacso y+hghb f;7k;/)nh ll at a wall;;/ +kbgh ncho7hys) f 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 r yi4: ck (qb/fvq;yw1oesult when 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 radiation axijpw)uc/7j35h 4lz g t a rate of 4 /ju )5hxgjpzl3i7wcabout 200 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 water” left in the 50-gal(8ok ft;ta 4u esq.+vo (185-L) water heater. This suggest+keo.uatfv(qt 8 so; 4s 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 su-s o-2flbc1r fdq9g;z 0 a6fcvrface 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.    $^{\circ} C$