What happens to the work done when a jar of orab ,y*hr:bhyb3nge juice is vigorously shaken?

When a hot object warms a cooler object, does temperatu 5i+s9o p6yvn7h7tzsg re flow between them? Are the temperatu7 v7g +psznys65it9ohre changes of the two objects equal?

(a) If two objects of differenji-;mfc8u9w9jo*f .q sd9 tkm t temperatures are placed in contact, will heat naturally flow from the object with higher internal energy to the object with lower internal energy? (b) Is iim-c;98ok9 umj*d t wq9.s ffjt 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 0axq5u,b ;t+r )jurqy 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 evening. ,u0 tbrruxa5y)q;+jqExplain.

The specific heat of water is quite large. Explarl7a.hv(l;) jt n yz8ein why this fact makes water particularly good for heating systems (that is,nthy) e8(z .;j7l lrav hot-water radiators).

Why does water in a metal cantekt +lxefn :vkavyd+8+pm7y.4 en stay cooler if the cloth jacket surrounding the canteen is kept moif a4ydtem7nx+kl8+v+ p.: vkyst?

Explain why burns caused by steam on the skin are often more se)agzd/)p7*tgrg8tdia 3 zof: :oxu +pvere than burns caused by water:z i7+ptdpgxr)tou/zg:f*) 38 gd aoa at 100 $^{\circ} C$ .

Explain why water cools (its temperature drops) when it evaporates,(9wfu1xd b3 fg using the concepts ofu9dfbgxw(f1 3 latent heat and internal energy.

Will potatoes cook faster if *vbrhpf u*8uvd5zy ,:the water is boiling faster?

Does an ordinary electric fan cool the air? Why or why nk1vhb,i5wj 9u3dv x n/ot? If not, why use it?

Very high in the Earth’s atmosphere, the temperature canpd21wgf8: esq be 700 $^{\circ} C$ . Yet an animal there would freeze to death rather than roast. Explain.

Explorers on failed Arctic expeditions have survived by covering them / 7 ;xc/xha*mrmvoo+gselves with snow.g;ah o/mxvm 7ocr +/x* Why would they do that?

Why is wet sand at the beach cooler to walk on than dry sandqcttg39jim. *h *0bh43g. r8 ul k.kq)emgckd?

If you hear that an object has “high heat content,” does that mean that its temzwwj l ; (pl,e+r:5sphperature is high? Explaie:+l pszwp j,l ;r(5hwn.

When hot-air furnaces are used to heat a house, why is it important l/a6be 7 xril:c6 xbh4that there be a vent for air to return to the furnace? What cib6/ xbh le 6xar7:4lhappens if this vent is blocked by a bookcase?

Ceiling fans are sometimes reversible, so that twefy3b6 w5y5a hey drive the air down in one season and pull it up in another season. Which way should you set5a5yewwbf y 63 the fan for summer? For winter?

Down sleeping bags and parkminhiu8 z;u:.qc4jrfmc4 /i9as are often specified as so many inches or centimeters of loft, the actual thickness of the garme4 48mcimu qnch :if./9uzj;ir nt when it is fluffed up. Explain.

Microprocessor chips have a “heat sink” gluaz5mlwi /s 2s)ed on top that looks like a series of fins. Why is it shaped like thz)il2 ss/aw 5mat?

Sea breezes are often encountered on sunny days at the sh 2z(cuqt.:oir w (x;bohidy*- b odk14ore of a large body of water. Explain in light of the fact that the temperature of the land rd1 i4 *(.t h-dy wozqkbx:io2;buor( cises more rapidly than that of the nearby water.

The floor of a house on a foundation under which the air can flh7r u3rzvy.yth dw/ :n: tm *itw.n97jow is often cooler than a floor that rests directly on the ground (such as a concretenh. hurwny *:.t3 jrt:7mdv 9ty7 zw/i 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 8 zdih7 tp (hgl 7lp9-b7amanw5 mrn/,taken with the thermometer in the sha9z7 mgnmaitp7lbr7dwh5 8pa/l(,-nh de.

A premature baby in an incubator can be dangerously corsw0p7i: o;ov oled even when the air temperature in the incubator is warvopwso 7;r i0:m. Explain.

Why is the liner of a thermos bottle silvered (Fig. 14–15), and a:lr-9in 9w bnwhy does it have a vacuum between its two wal b 9-a9rlnin:wls?

Imagine you have a wall that is very well insulated — it has a very high thermalk jeuhyd kn8d ,x5 km:lng8l3k3/)t t/ r3ge tm3/5y 8k)hx:lkud nltd/ kj8k,nesistance, $R_1$ 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 frwyma*d1lv *.gco(b fj xgv34)j;m5kc zu :-xollowing 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) Heavy curtains reduce which of these j xg*roml c kxj.v*v1zcay f -)u(;d35gmb:4 wheat losses? Explain in detail.

A piece of wood lying in the Sun absorbs more heat than a piece of shiny mee3xp8lwd npki t3/4 v qs9; (pvx88kjgtal. Yet the wood;3kxw p38 ig9d/skvntplexj(48p8 qv feels less hot than the metal when you pick it up. Explain.

The Earth cools off at night much more quickly when the wew cy53rv;r be(ather is clear than when cloudr;wv3ry( 5e bcy. Why?

An “emergency blanket” is a thin shiny (metal coated) plastic fa7zbh3sr; 5oz k(t yyd5* ,plzoil. Explain how it can help to keep an immobile person zpak7l3r tz5*s zy;h,b yd(o5warm.

Explain why cities situated by the ocv5qczboab7 sz c1+;wot/b /b, ean tend to have less extreme temperatures than inland cities a5bab,q cztb1c bo7so/v+w; z /t the same latitude.

  How much heat (in joules) is reqie0g5kyznj 36 uired to raise the temperature of 30.0 kg of wat0jnk6i5e zy3g er from 15 $^{\circ} C$ to 95 $^{\circ} C$ ?    $ \times10^{7 }\,J$

  To what temperature will 7700 J of heat raise 3.0 kg of water that is initi7 zk..3pofmsw ally a.k7.pozw sf3mt 10.0 $^{\circ} C$ ?    $^{\circ} C$

  An average active person consum whx93 bwn3uv2es 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 syc4x;h: u3blcz stem of units. One Btu is defined as the heat needed to raise4zlc;x hc:3ub 1 lb of water by 1 F $^{\circ} $ . Show that
1Btu = 0.252kcal=1055J

  A water heater can genf4 fq+a x5bn3jerate $32,000\,kJ/h$ 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 lonmnz2 /y4 mb0s m3ymjl:g it will take to heatmy4 mjnsl:/2bmm03y z 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 brakn5 a+e,(ly ywpes are used to bring a 1200-kg car to rest from a speed elw5+(, y nypaof $95\,km/h$ ?    kcal

  An automobile cooling s n+pvzgsn:,8 dq5t p4zystem holds 16 L of water. How much heat does it absorb if :n nq+p45d8g,zpvszt its temperature rises from 20$^{\circ}C $ to 90$^{\circ} C$?    $ \times10^{ 6}\,J$

  What is the specific heat of a metal substance qzk7j(q /q4 :9e tpgn9er0scxif 135 kJ of heat is needed to raisqx( e:n99r4 qtgjkc/qze0 7p se 5.1 kg of the metal from 18.0$^{\circ}C $ to 31.5$^{\circ} C$ ?    $J/kg\cdot\,C^{\circ} $

  Samples of copper, aluminum, and water experience the same temperature rimrpvp m6o-)g9 se when they absorb the same amount of heat. What is the ratio)m vp omp-gr96 of their masses? [Hint: See Table 14–1.]$m_{Cu}$ : $m_{Al}$ : $m_{H_2O}$ =    :    :   

  A 35-g glass thermometer reads 21.60 3cj5jpvu -cs$^{\circ} C$ 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 copper at 28, pcp 9 dnf90th4o5b wwg*3eim5$^{\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 = 4c2 9ix9sv)ko; .t 3m ozxvset$0.4\,kg$) 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 it,j5, vsvpj t+xj)gr+s 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 coffeepo, x.ei ttxz97tx l+0/ssk4wgft to bring to a boil 0.75 L of water initi4. 7tgs0 txkx ewtzi,/+f9xlsally 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 r1v;:/q-mc 3fjyzt h84z goqp 75 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 temrzf3:qyqv h c;4 8zgjt p1om/-perature of the mixture is 15.0$^{\circ}C $ , and its temperature after ignition is 53.5$^{\circ} C$ .    Cal

  When a 290-g piece ogz6 gmccsb mf:7x3. 7jf 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 ham*tp qg;vt;2ilgx n6t,mer has a speed of $6.5\,m/s$ just before it strikes a nail (Fig. 14–17) and is brought to rest. Estimate the temperature rise of a 14-g iron nail generated by 10 such hammer blows done in quick succession. Assume the nail absorbs all the energy.    $C^{\circ} $

  The heat capacity, C, of an object is defined as the amount of heat needed to 0 190i d snjy/ey;fthjry6rw4ewbr-5 raise its temperatuy 9twh dy46rjs1-f;jwer5bry/ 0en i0re 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 o+0e phjsfq vt-o6,,w that is initially at 20$^{\circ} C$?    $ \times10^{6 }\,J$

  A 0.095-kg aluminium sphere is dropped from the roof of ayz b 0fco):k3s 45-m-high building. If 65% of the thermal eneryc kos0:f )3zbgy 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 heawc5)k4x si +1 ol lqk4 bva7zp.fw(fq3t in 30 min by evaporation of water fifbk7pl qc voqsz+453fa (wl1k. )xw4rom 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 dropp+psxq;*t)uebij ( 9f ged into an insulated container of liquid nitrogen. How( b;p9 xq*)uief+stg j much nitrogen evaporates 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 -8.39jhb0 yq/ dah5 $^{\circ} C$ 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 830cslqk((6 6im 3shkrp. 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 8.0 L of wate ezcq7m6mg:*dr 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 ridez qge c:m*6md7r 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 100ybe8hh4z(w/a + fu:r k$^{\circ} C$ 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 mercuryerl:(he0 g9wm 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 travel5;fc3g-esm *: ejyqja0il7tg ing 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 tbso9n:h4v/0r4rf dp $6.4\,m/s$ 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 fod) 0iwh2-e9svlv jcu2rensic investigator notes that the 8.2-g lead bullet that was stopped in a doorframe apparently melted completely dh- suw9ijlec2v2v 0)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 alumnr g) r5yskfz9xji-vx5.n(.g v7g +lbinum rod with 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 conduction0fik+xq 8ec 33z7u gchc/pd m. in Example 14–10, assuming that there are strong gusty winds and the external temperature is cgfi78+q /cd03xe.zhm ck u3 p-5$^{\circ} C$   $ \times10^{4 }$ W

  (a) How much power is radiated byb(t,s zm x.sx0o.t4xt a tungsten 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 flf )hsx fjk *3i*u3go2zows by conduction from the blood cap)z 3 jx2kh *fsoif3*ugillaries beneath the skin to the body’s surface area of $1.5\,m^2$ If the temperature difference is 0.50 $C^{\circ} $ , estimate the average distance of capillaries below the skin surface.    $ \times10^{-4 }$ m

  Two rooms, each a cube 4.0 m per side, share a 12-cm-thick brick walldq)1rx 3bm.d v. Because of a number of 100-W ligqd 3.v)1xdb mrhtbulbs 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 to qa cq, p/2 j9di:n9t1m)hxzpe 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-sectiona cfgqd ( gis2l21gn26il area are attached end tfndl(g6q2 g2g i1is c2o end (Fig. 14–18). The copper end is 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 t ycb-a h(r+,3frid-c0wjjv 8jhe whole Earth receives enerr+(0jafdw-3y 8 r-hjbvij, ccgy 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 tve:li nez8ee (3jgp26la p)m2hrough a glass bulb that has a radius 8j l6eel3g i2(2e)pv: eapmzn 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 a house i6 whmb gp-fp (.;:k7yhtye8fcome 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 rate of heat hyfi (67f.wp; kebt8mhg:-yp 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 gl8pdz zdego6(v:52dff um;ah :bk. +ji ass separated by an air space, Fig. 14–20. (a) Show that the rate of heat flow through such a window by conduction is giv2 v 6+degbo zz.mk da(hp8:j;:uffd5ien 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 lon7+f a f7a52t4ctm ati-hcf;o pg should 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 containsdcw9 1z-xd g2d d78vgf about 0.20 kg 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 ocea+,0aw ,gzjo5 c) conu1trek)r ns, estimate the heat liberated when a cube of ocean water, 1 km on each side, is cooled bezo , jo5ak)w,r gc1)t0 cru+ny 1 K. (Approximate the ocean water as pure water for this estimate.)    $ \times10^{ 15}\,J$

  A 15-g lead bullet is tested by firing it into a fixed block of wood with a ma 8xh/(hvju*ce ss 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 temperaturx*8 e huhc(j/ve 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 th t m57sys60 arpj-njh3e Sun, assuming it to be a perfect emitter rtp jjy as3s7h-m0 n65at $T\,=\,5500K$ 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 generate rw: u;yj0 7ji hi62yc ,wb1xzo$200kcal/h$ 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 falls a g* uf.8/ tb)sjuy- anbvertical height of 140 m before striking tha/b-bf.t y s)n8uju g*e 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;engs n y 1te/ q7;jvq7.gppja8 d5t bzl5:l)p pail of water initially at : ag;qsgp b 57 nn.vdpyqzl5)/t7e ;jtp1l8ej20.0$^{\circ} C$. 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 surface alepsmqbw0hyufc 2q fnw76 + bw1y3/)) rencf)mu s7 bl b+e2y1q630yw q)w/hpfwa $1.2\,m^2$ 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 aw77ts7 8+p1qnr 8epn m3h bj c5)dqmnkbout $950\,kcal/h$ 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 condur wcx-.*sx7 5yqr wbf2cted from the interior of the body to the surface. Assume that the thickness of tissu q52wy.wrxb fs7x*c-r e 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-insulatedt.hel4xtwq6ny-0 r )h.4 gnsl walls 17.5 cm thick (assume conductivity of air) and area wgeq.- sxhlyl6)4.n0nhr tt4 $410\,m^2$ 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 tm1xzc ;6yvm*r 3( yz x9f7mqocraveling 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, take inc4g0p, s,x37 tbtork1zqa0zwto account radiation from the leaf to calculate how much water0 7ktbx3o1 tsz, gzq0ap,4rc w must be transpired (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. Iv,:) ks zy/k+t sz.gmhf its initial tempera t+zgszy. ,h :)s/mkkvture 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 increases abouu2cgf(pbh*7zj x y;3xv c9s7qt 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 so2mx5s w r;b+v;vjz2bwft rubber ball at a wall until they are about to drop due to dehydration and exhaustion. Assume that the bajv m;w2sz;5+2bx wrvb ll 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 eq ybn o0d0bvu8k/6vq.gual 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 radevrvuvso .+9f ;gx0v4iation at a rate of about 200 W. Estimate how lsrfguv9xv.+ ; 40vvoeong 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 wattyo1x -wpj93e(n af:ter” left in the 50-gal (185-L) water heater. Thio n-1ta:w pjyxt93fe (s suggests that the tank has emptied and refilled with water at roughly 10$^{\circ} C$. (a) How much energy does it take to reheat the water to 50$^{\circ} C$? (b) How long would it take if the heater output is 9500 W?    s

  The temperature of the glass surface c4.+ch6f 7s- 4yrwr:lnrqegp 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.    $^{\circ} C$