What happens to the work done when a jar of orangmkqbp/u: l l3y04jd xi6: hguo1.0rgd e juice is vigorously shaken?

When a hot object warms a cooler object, does temperature flow betw.qzvlp/c )bt :ee6 n/peen them? Are the tempera lb ep 6/:cp/e.qvntz)ture changes of the two objects equal?

(a) If two objects of different temperf*( 58 y zlcmyti3d-rhatures are placed in contact, will heat naturally flow from the object with higher internal energy to the object with lower internal energy? (b) Is it possible for heat to flow even if the internal energies of the two objects are the saf(h3 tc*8z5ldm-y ry ime? Explain.

In warm regions where tropq35e02cl6jfkd:e/d: 9 zugf y+pe rgeical plants grow but the temperature may drop below freezing a fe95re+yf/ce6kg:l z:02 g eju fpq3ddew times in the winter, the 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. Explain why this fact make8m4 erqyh 0n, fb.-povs water particularly good for heating syst8hb-4 fem vn0.y o,rqpems (that is, hot-water radiators).

Why does water in a metal canteen stay cooler if the cloth jacz,8kwmw ()l ggrkxb.6e* aeo.8 )urfvket surrounding the ew *),alog xbv6. k ()ge 8wzkfm8.urrcanteen is kept moist?

Explain why burns caused by steam on the skin are often more severe than r cfd--lmygv-z oocz7g:q 4* 9bgh2a .burns caused by w.7z cqdgcbhgo 9g2m - y*r4-lovzf -a:ater at 100 $^{\circ} C$ .

Explain why water cools (its temperature drops) when it evaporates, using 5cc 1ohda7ocm11c4 dmthe concepts of latent heat and int7cc5cddo11 h41ommc a ernal energy.

Will potatoes cook faster if th9n 6/ )isqb-kxoo7qt+ e5fmzee water is boiling faster?

Does an ordinary electric fan cool the air? Why or b.f09dfpkfss7m j3r /why not? If not, why use it?

Very high in the Earth’s ahwq2k4lkpp11 tmosphere, the temperature can be 700 $^{\circ} C$ . Yet an animal there would freeze to death rather than roast. Explain.

Explorers on failed Arctic expeditionsg jydtn zd/q/ cs hw+-e6+;j(s have survived by covering themselves with snow. Why would they d js+y/t 6wdce (hnqzj-d+sg/; o that?

Why is wet sand at the beach cooler to walk on than :)d 9tai0aea bdry sand?

If you hear that an object has “hir wnfc(;( yoj( )b1h5- mjdgergh heat content,” does that mean that its temperature is high? Edf)j1gy(c5 ;bme rjo r-( nwh(xplain.

When hot-air furnaces are used to heat;xt**g4/ho .jjbsag/yj z2 wt a house, why is it important that there be a vent for air to return to the furnace? What happens if this vent i*4 j zo.*wtjh/xja/s2; bggy ts blocked by a bookcase?

Ceiling fans are sometijkcg9sk6u k76 mes reversible, so that they drive the air down in one season and 69kjk6 g 7cskupull it up in another season. Which way should you set the fan for summer? For winter?

Down sleeping bags and parkas are o u)+rm;c r*j.6o /vlewrt*h aqften specified as so many inches or centimeters of loft, the actual thickness of the garmentretaqulj.o/ cr*hv) +w ;6m*r when it is fluffed up. Explain.

Microprocessor chips have a “heat sink” g;q zv,mikt 1z5up:c)x lued on top that looks like a series of fins. Whytciu;k)pmz, z1xv 5: q is it shaped like that?

Sea breezes are often encountered on sunny days at the shore of a large w-p2d6x bj4li5d0 dh)i ty5tcbody of water. Explain in light of the fact that the temperatupb hil 5) dtx60widt2j54cd-yre of the land rises more rapidly than that of the nearby water.

The floor of a house on a foundation under which the air cako l:7b1mcw8qa6k mwvf;2n d-n flow is often cooler than a floor that rests directly on the ground (such as a concrete slab foundation). Explain. ;fdm7akvwk-c2 1 o8 :l6nmbwq

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

Explain why air temperaturem wi 35tg)ju.w 8pjgz7 readings are always taken with the thermometer in thtw)8gg3w.u75z ij pm je shade.

A premature baby in an incubator6t8- +3xj m0sr frg* z c0trdinpkcf(/ can be dangerously cooled even when the air temperat0m0jcc3 rtrgd6p nir8 +/ ktx-z f(sf*ure in the incubator is warm. Explain.

Why is the liner of a thermos bottle sil4ve3oj 4 9jbqnvered (Fig. 14–15), and why does it have a vacuum between its two walls? jb3no j v4qe49

Imagine you have a wall that is very well insulated — it has xa mtxic6 03j n+1i1yza very high thermal resj0m+xi 1i6z3ancx1t y istance, $R_1$ 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 foljx6ko0hv3 yb )lowing processes: (1) ventilation around edges; (2) through the frame, particularly if it is metal; (3) through the glass panes; and (4) radiation. (a) For the first three, what is (are) the mechanism(s): conduction, convection, or radiation? (b) 3kyo6vb0)xh jHeavy curtains reduce which of these heat losses? Explain in detail.

A piece of wood lying in the Sun absorbs more heat than a piece of sa,pxy7.vnt**sa1 u lphiny metal. Yet the wood feels less hot than the metal when you pick it up. a* .u 7sx,n1l*v pytpaExplain.

The Earth cools off at night much : c8t a amrui50+t6srq-(qkd cmore quickly when the weather is clear than when cloudy. Why?m(rak0+-a 5it:q 6c utr csdq8

An “emergency blanket” is a thin ml yahbo7 pqz(ymz7ho*3 gtl1i .;/8 fshiny (metal coated) plastic foil. Explain how it can help to keep an immobile per(z3a f/zlgo17h;op 8ytq.lm*bmi yh7son warm.

Explain why cities situated by the ocean c x0e.xx1 pmh0tend to have less extreme temperatures tha0hepx. cm0 x1xn inland cities at the same latitude.

  How much heat (in joules7:b,mqs xo: vk) is required to raise the temperature of 30.0 kg of water bk,o:7vxq : smfrom 15 $^{\circ} C$ to 95 $^{\circ} C$ ?    $ \times10^{7 }\,J$

  To what temperature will 7700 J of heat raise 3.vs-:fkx0byl scp2 y:h9 t 62zp0 kg of water that is initially 9pvyyf:sts2c pbxk lzh62:0 -at 10.0 $^{\circ} C$ ?    $^{\circ} C$

  An average active person consumfpgut 5*(cf ++xnkrq*nl z+ kw;s(/b wes 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 o q9a mbslo:92*cw0 wz+d keh sryal/;,f units. One Btu is d ,s0 lrhmk*2b 9:ce wazo+;wyds/q9 alefined as the heat needed to raise 1 lb of water by 1 F $^{\circ} $ . Show that
1Btu = 0.252kcal=1055J

  A water heater can gemf)d91hy 8ltniaa 2 -onerate $32,000\,kJ/h$ How much water can it heat from 15 $^{\circ} C$ to 50 $^{\circ} C$ per hour?    kg/h

  A small immersion heater ise o .gtucs)p42 rated at 350 W. Estimate how long it will take to heat a cup of soup (assume this is 250 mL of water) fromg4c.)so eup2t 20$^{\circ} C$ to 60$^{\circ} C$ .    min

  How many kilocalories are generated when the brakes are used to bpvqkkb+c 3e,z pi4q dp4 ,-j1aring a 1200-kg car to rest from a sp,pj q1 4d -z vpkikb4+cpeqa,3eed of $95\,km/h$ ?    kcal

  An automobile cooling system holds 16 L of water. How)s* w/nit w:pc much heat does it absorb if its temperature ris:is/wp)n t*wces from 20$^{\circ}C $ to 90$^{\circ} C$?    $ \times10^{ 6}\,J$

  What is the specific heat of a metal substance if 135 kJ of he8ja )zny)7xz6jaqt 0bn9 qz5iat is needed to raise 5.1 n zb qy7nq8)5z60aix )tjja z9kg of the metal from 18.0$^{\circ}C $ to 31.5$^{\circ} C$ ?    $J/kg\cdot\,C^{\circ} $

  Samples of copper, aluminum, and watery58h;nfp0 dy pr3 ,::7v x ja(hioltzp experience the same temperature rise when they absorb the same amount o5lyzyrodpf:p;av0:(ih8 p3x jt7nh , f 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 readw i -7mynlw20m yuwe.;s 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 wh8w2pxejn8(l8vv (8yi4t .tg 6nhbakoen a 245-g block of copper at 285$^{\circ}C $ is placed in a 145-g aluminum calorimeter cup containing 825 g of water at 12.0$^{\circ} C$ ? $T_{eq}$ =    $^{\circ} C$

  A hot iron horseshoe (mass =lei;8fc6yb+ w $0.4\,kg$) 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( 8vu62z6i :lga yjuuy vtxz:e5dld 23 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 0.7cqi9w6vj m* 8e5 L of water initia*i m6ecwqv8j 9lly at 8.0$^{\circ}C$? Assume that the part of the pot which is heated with the water is made of 360 g of aluminum, and that no water boils away. $\approx$    min (Round to the nearest integer)

  Estimate the Calorie content of 75 g of candy from the fol 40 n,qao3 7lj8plgefolowing measurements. A 15-g sample of the candy i73loeqpj04ag8n,l f o s 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 o:gepib 0vx 3wrdo:-1u 2nr- wbvma), lc(:vx kf 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 has a speed of vnug6)usc9w) a8:q pgl t b-b6$6.5\,m/s$ 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, oh36 ldrg(k)w95 lnswed1u7x z3t7nm mf an object is defined as the amount of heat needed to raise its tempeewn13t)nr7 6xdl w 7shmglm(93dz5 kurature 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 silverde6qly1sn s14 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-hig61 itd 8ht:m34wnt 4coorq wg8h building. If 65% of the thermal energy produced when it hits the ground ist3 wcgo mo8 8twnq41tdhi:r64 absorbed by the sphere, what is its temperature increase?    $C^{\circ}$

  During exercise, a person may give off 180 kcal of heat in 30 zas6zlr4 2ei:lnf5wu-(8mjemin by evaporation of water from the skinn 8-5fl2le6mu(i4 jsz :zrw ea. 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 po,nk 7(e3,cpbaa ztd +zint is dropped into an insulated container of liquid nitrogen. How much nitrogen evaporates if it is at its boiling point of 77 K and has a latentzk,bp+at,(e7dz n3c a 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 t6 )lcrlp2 :dl r/o abv2 ne+qimvt;.8-8.5 $^{\circ} C$ 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 con;8 bifgj+ z9gl of::*zk rtry1tains 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 consuxyhc7 fvn29, ymes 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? (2h vx,nyy7cf9 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 1j/xtoq mr 9vij85i0 0xo:z7 no00$^{\circ} C$ 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 mercury ,w ).qvnod (h:xr)-s acbi :rhzq,9ziis $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 travelipm-bk+ljfzpgku/;-b n4 9tx s gyep7+296h stng 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 mov mql09k6jl5 pving 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 fjbv ky:-f9u v0orensic investigator notes that the 8.2-g lead bullet that was stopped in a doorframe apparently melted completely on impact. yv-fb:0 kuj9v 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 kepteu-ary i hh64d: iqriqtyo3bg/ h/ m:b0g:d+- 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 hh,athvfo2b+ /gr 9kx g ot38z/eat flow by conduction in Example 14–10, assuming that there are strong gusty wi /3zhxo9bfv8hgg/o tk+, a tr2nds and the external temperature is -5$^{\circ} C$   $ \times10^{4 }$ W

  (a) How much power is radiated by a tungste(z3nkcd v0 h)vn 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 flows by conduction from the1 +hl*:v bs6u2 mk0o8m o9tbiyr;us bh blood capillaries beneath t 8b9 iu;6m tokybmu*r 1h:lsb +02hosvhe 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 cubeh8pnyioi9e9gf (( 6 bg 4.0 m per side, share a 12-cm-thick brick wall. Because of a number of 100-W lightbulbs in one room, the air iyiio(9 n eb89h fgpg(6s 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 of ice adve6 9a:h 5j5cc fpaw)umio1;t 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 rt+ wi99wu1dy*zmnr 6 vd q2e)xod of the same length and cross-sectional area are attached end to end (Fig. 14–18). The copper end is placed in a furnace maintd wi6)zu+ 2t*mx e1 yrnqvd99wained 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 w cq2 *o.;hc30hergdj,dgo7a. tvjr/ vhich the whole Earth receives ecorjc0*./qvhj;grgo2,h.d 37t evda nergy 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 throug2yi3kq s ,,e2p / ogyzitv;e6lh a glass bulb that has a radius of 3.0 cm and is 1.0 mm thick.2yze ip3,oqy i2, sk6/t;eg vl 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 a huo5rs vat7/5r ouse come mainly from a 4.0-in. layer of brick and an R-19 layer of insulation, as shown in Fig. 14–ra7 5vst u/r5o19. 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 separa1nrj ,tb u1--ffb u-eited by an air space, Fig. 14–20. (a) Show that the rate of heat flow through such a window by conduction iseubrf nf t-1i--u 1bj, given by
$\frac{Q}{t}$ = $\frac{A(T_2-T_1)}{l_2/k_1+l_2/k_2+l_3/k_3}$,
where $k_1$,$k_2$ and $k_3$ are the thermal conductivities for glass, air, and glass, respectively. (b) Generalize this expression for any number of materials placed next to one another.

  Approximately how long should it take 11.0 kg of ice gez*2 awy9 g ;zqu68svat 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 liqrn; g4cl 28mlnuid 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 ee( m/pzo6 i2xanergy 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 oci(a p6/zemo 2xean water as pure water for this estimate.)    $ \times10^{ 15}\,J$

  A 15-g lead bullet is tested by firingy;4p 6ug;pmfm 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, the system has a temperature rise measured as 0.020 g4u;pfy6mmp; $C^{\circ} $. Estimate the entering speed of the bullet.    m/s

  (a) Find the total power radiated into space by the1vz*r 39p mp .:vthhcik+mqg: Sun, assuming it to be a perfect em9m3 +rqhp:c v. z kth*i:pvg1mitter 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 activityn2 qe jv9f 9s.7nk2fbz, a 70-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 a cliff and falltfsn22n-: b2v5 fh cams a vertical height of 140 m before striking the ground. Estimatnt:-5 csfmvf2h a22 bne 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 o ezqyq*2x,tr ,f water initially at *q,z,e xq 2yrt20.0$^{\circ} C$. 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 sumz 4t 6v/nh:.6sc( a +ayssehkrface area m a :zhch6se/kny(at+ 6s.vs 4$1.2\,m^2$ 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 oxj8 wq1x hg5 yo.vf6alg:y*x4f 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 whqp* 0 ; ft is4) 2uk)fkzfd28f1rdwoiiich heat can be conducted from the interior of the body to the surface. Assume that tdui )wkk frzds2q f8fto0f4;2)i 1p*ihe 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 (assumeb4kes1( ms-pf.fg1 ;ykq9kyk conductivity of air) and a(p;ksg1q4fsyy e k1 b9.-fkkmrea $410\,m^2$ 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 rbc+dutsv//*l. wk l n*fu4 m($220\,m/s$ 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 radiation fromv407n8qzlid( k s-m in the leaf to calculate how much water must be transpired (evaporated) by the leaf per hour to maintain a tem vqmn -04li (87nidkzsperature of 35$^{\circ} C$.    g/h

  An iron meteorite melts when it enters the Earth’s atmob v55epabv,9 2u onpu0sphere. If its initial tempera b 5benou0 pvau59,2vpture 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 q ty/8x3n t )rfetw*co68 z.kr9ohd.y 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 (Fig. 14–22), two peopl lm v(cag*vt4,e 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(vgtaml,4 vc* 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 finalpz5aluo*xsj3my 1* 5g blm9.i result when equal masses of ice at 0$^{\circ} C$ and steam at 100$^{\circ}C $ are mixed together?

  In a cold environmenth9jy; 2m zphlix2s8h 55kjk4b, a person can lose heat by conduction and radiation at a rate of about 200 W. Estimate how long it would take for the body temperature to drop fro5ks jjphh9m4;x2 l2 byzhk i85m 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 509,)dkhdnwpep f/f2-u -gal (185-L) water heater. This suggests fu fp-k) /epd2n,dh w9that 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 gl1d0l n nfp jcl/1cu-3nass 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.    $^{\circ} C$