What happens to the work done when a jar of orange juim bw8kxpa7-8vce is vigorously shaken?

When a hot object warswzna+/ 7 6jkdw2wp us 0.n7vgms a cooler object, does temperature flow between them? Are the temperature changes u.zj07ks+pv 7nw g/wdw2 n6asof the two objects equal?

(a) If two objects of differenjnxa88 wz bn,+t temperatures are placed in contact, will heat naturally flonax,z+w 8b8jnw 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 same? Explain.

In warm regions where tropical kaewo4w5+dx wq (,wi a/-/bqs plants grow but the temperature may drop below freezing a few times in the winter, the destruction of sensitive plants due+ /kwdoas, wb(/-q iq 4e5waxw to freezing can be reduced by watering them in the evening. Explain.

The specific heat of water is quite large. Etq bv20v2r8 gf1z6ayi; j/kn explain why this fact makes water particularly good for heating systems (that is, hot-water ra2ab vg1n/t6iy fv2 e8jz0qk;rdiators).

Why does water in a metal canteen stay cooler if the cloth jacket surro)yr/1f 0pbpsx unding the canteen is ke )/b1 y0rpsxfppt moist?

Explain why burns caused by steam on the skin are ofzf;oc 4 mzi+/hhcz:x5 ten more severe than burns causexc5;:ho/zzzm if+ hc4 d by water at 100 $^{\circ} C$ .

Explain why water cools (its temperat6u1y5 ,y6 vh+myhpm*lvv 3kehure drops) when it evaporates, using the concepts of ll6hyku1ve5h, +v mm yvhy6*p 3atent heat and internal energy.

Will potatoes cook faster if the water is boiling fasterki- ;9,: a)y keukz1;rg*pxdfn uit 4y?

Does an ordinary electric fan cool the air? Why or why not? If not, why usemd4jm) i9yu vlu/cbf 15xv .w: it?

Very high in the Earth’s atmospherbzaa5 phl2cm)*f-r ,v e, the temperature can be 700 $^{\circ} C$ . Yet an animal there would freeze to death rather than roast. Explain.

Explorers on failed Arctic expeditio ;zqnjdd t(h6j/w *v jdeigc891sb+7uns have survived by covering themselves with snow. Why would they do thatdu* iw t8ejh9dj/6z;q1cb7+(gnd s vj?

Why is wet sand at the beach cooler to walk on twu ks+,:x* x:zve(q yqhan dry sand?

If you hear that an object has “high heat content,” does that mean that irx; n izm+j19:l* zfents temperature is high? E+j: xz;9*nzifr 1 elnmxplain.

When hot-air furnaces are used to heat a house, why is it important that0bk7kofbq -r (car:xr)f4 b:e there be a vent for air to return to the furnace? What happens if b-re:rcqx b)f (4ao b7f0krk: this vent is blocked by a bookcase?

Ceiling fans are sometimes reversible, so that they drc*9+qcw0gjp j5o qsu.ive the air down in one season and pull it up in another season. Whic 9jcgcu5.qpwq+j *0 soh way should you set the fan for summer? For winter?

Down sleeping bags and parkas are often specified as so mancd(;/v z o.*dh7fr 7idunr 4fngb4,pmy inches or centimeters of loft, the af;nbp,uc o4hidm .z4n/7rrd(*df 7 gv ctual thickness of the garment when it is fluffed up. Explain.

Microprocessor chips have a “heat sink” glued on top that loo f b8ey l0odpc+ y qk3bjy6d7yzlz8mfl0b,71 (ks like a series of fins. Why is it shaped like th qy, 80b16jzyyfboy0dz+cl 7(dllf78m bk3pe at?

Sea breezes are often encountered on sunny days at the shore of a large body of 8ori a)ra53u48am fox water. Explain in light of the faco5rfumiraa48 a o 8)x3t that the temperature of the land rises more rapidly than that of the nearby water.

The floor of a house on a foundation under whicifn kaaa 5*2uq9 vt4h*h the air can flow is often cooler than ankt9a v4a* h*25uqfia floor that rests directly on the ground (such as a concrete slab foundation). Explain.

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

Explain why air tempehpk 2kizd0m;i(+qb 7prature readings are always taken with the thermometer in the shade. bkh;p0di(+7pzmk 2iq

A premature baby in an incubator can be dangerously cooled even when 0w4i3vcs v q)3*kl qc)fjt 1fx(q4 zitthe air temperaturelz 1f qcxc)(3t jtqvf3sk4 v0)iiw* 4q in the incubator is warm. Explain.

Why is the liner of a thermos b6 k c)l2cx gosga/mu) 1np9*sbottle silvered (Fig. 14–15), and why does it have a vc1 96 o )*nxl/gkubs2gmp) sacacuum between its two walls?

Imagine you have a wall that is very wel7jh*7xs6d kek+ pab2 dfk 7o5tl insulated — it has a very high thermal resistaeh2d7b7*txf5k7d j6ksak +o pnce, $R_1$ 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 thr . t7hragrp8nck .qax1- /w.aaough windows 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, convection, or a7t -khgq8/. 1xcrnwar. aa.pradiation? (b) Heavy curtains reduce which of these heat losses? Explain in detail.

A piece of wood lying in the Sun absorbs more heat thau4wll, +kt7irn a piece of shiny metal. Yet the wood feels less hot than the metal when you pick it up. Explain. t+wikl,ur7l 4

The Earth cools off at night much ,(w 7qpbac vf-mn9r -ymore quickly when the weather is clear than when c7q -ya-vrwc,p( bm9 fnloudy. Why?

An “emergency blankea+mr exln -.o8t” is a thin shiny (metal coated) plastic foil. Explain how it can helpm ao.-+ er8nxl to keep an immobile person warm.

Explain why cities situated by the ocean tend to have less extreme temperaturei8 gb3 9wz0 g(emb-lres than inland cities at the sa -ib3 r8w 0bgzeg9e(lmme latitude.

  How much heat (in joules) is required to raise the temperature of 30.0 kgz :;4ng69pasmanih *r9 1 vkve of water from 15 ;zn 6 eimrk1an9gp* :sh4avv9$^{\circ} C$ to 95 $^{\circ} C$ ?    $ \times10^{7 }\,J$

  To what temperature will 77 g;i09bkln+6lmwon j 900 J of heat raise 3.0 kg of water that is initially at6g9 ;w9j+n k ll0imobn 10.0 $^{\circ} C$ ?    $^{\circ} C$

  An average active person consumema m ,1/f6gcb7 d*k:s.lutysls 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 Britishn+-75gy+,zbfna v x0 yh j)hxh system of units. One Btu is defined as the heat needed to raise 1 lb of wat-+f h zhj+xgn0,x)y y7hbv5an er by 1 F $^{\circ} $ . Show that
1Btu = 0.252kcal=1055J

  A water heater can generateckt6k lh07z9t $32,000\,kJ/h$ 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 lonew;1du ; 5(andje0 kcjg it will take to heat a cup of soup (assume thise;k eacn;1 5w0 djjdu( is 250 mL of water) from 20$^{\circ} C$ to 60$^{\circ} C$ .    min

  How many kilocalories are getb ylbp*f9.x -nerated when the brakes are used to bring a 1200-kg car to rest f*-xl9bp. tyfb rom a speed of $95\,km/h$ ?    kcal

  An automobile cooling system holds 16 .6 +g7fpn,j9jodv ifiL of water. How much heat does it absorb if its temperature rises fr,9n oid.+ fgfjj ivp76om 20$^{\circ}C $ to 90$^{\circ} C$?    $ \times10^{ 6}\,J$

  What is the specific heat of a metal substance if 135 kJ of w:4 7xs cof4 vxro pz2(8njxi2heat is needed to raise 5.1 kg of2oz owjx2nx(cir4x : sv4f p78 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 spva nj9/8*tsv1t ))u/sh 0css4qc a wtemperature rise when they absorb the same amount of heat. What is the ratio of their masses? cs4jsv)0/sswp)uq/hs tvta 9ca18 n *[Hint: See Table 14–1.]$m_{Cu}$ : $m_{Al}$ : $m_{H_2O}$ =    :    :   

  A 35-g glass thermometer 7d32otgcs 51c eyazl)reads 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 equilig88z6 q uzcs)/wr k1mebrium temperature 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 (mass gejw h2 *sr,c41 orgg*= $0.4\,kg$) 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 substinbst1b ear7:ksyu +n2 65eu0q9r2xt ance 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 coffeepot to bring to a bh ;4egjp e9e unq5j82loil 0.75 L of water initially a p5g ehq82enej;u 9lj4t 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 :3 ndj8n ruj,emeasurements. 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 d, jn 3:nrjue8of 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 ird; iczsg++ gm*on 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 hawhd ipe4af9h-bg-7n7mmer 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 definsfz w.y1p8pem +k1n5r ed as the amount of heat needed to raise its temperature 1 m efkpp5.1zyswn +r8by 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 at 28:esmr+la 67lgrntt.0$^{\circ} C$?    $ \times10^{6 }\,J$

  A 0.095-kg aluminium sphere is droppex3 d i2zfoo*c/d from the roof of a 45-m-high building. If 65% of the thermal energy produced when it hiti3zo /xd2*o fcs 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 evaporatioa36t pjrgo. m4n of water from the skiagmtop. j r436n. 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 meltinfku t7i v.,s3bnk. y1y:wz-t jg point is dropped into an insulated container of lk-i7sz,vktyyjt : .1fbnu3 w.iquid nitrogen. How 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 atl7m;x:og t,p kma 4bm6u33be f -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 contains 830 kg of;riy7 tya *u i vh2ei76nb,.mq 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 water o(w602,zns k1 b4ozn: swhg,g mwtic*bver the span of four hours. Making the approximation that all of the cyclist’s ene s260 ( cgszgzbbi1,no,:mk4w *wwnthrgy goes into evaporating this water 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,ykp wi2, vj49a dn3pw 100$^{\circ} C$ 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 1xh,llk:n rnz+n c*g1 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 travelinvg*ono md(wv z:+x2h5g 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 movingu5.gex-/g*r ucv( 8 sp0vkods 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 investiga2 wqepr:9)icitor notes that the 8.2-g lead bullet that was stopped in a doorframe apparently melted ec2p:)iw qi9rcompletely 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 d -cefho;w/s / cw5p9fsiameter 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 conduc)yn l 4:9vjz4 gfste92emx1 tlw(bst.tion in Example 14–10, assuming that there are strong guwxs4nmelbt:slz.2 4tv99 (f tey) 1gjsty winds and the external temperature is -5$^{\circ} C$   $ \times10^{4 }$ W

  (a) How much power is radiated by a tungsten sphere (emissivit/n:by,mrm d:.*ia3eiafh vu :y $e\,=\,0.35$) 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 2 r,;e 7sgzp of-)wqi4 8izs4efa*whn0 00 W of heat flows by conduction from the blood capillaries beneath the skin to the qf wn),4z0-7 e;ozg ia8is4pehs w*rf 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-wyl7o ro/vc7: oqyf:* thick brick wall. Because of a number of 100-W lightbulbs in one room, the ailoq7/or : ycw7f* oy:vr 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 melt a block of ice at ot:x r clq0f j8z3slsm/h.x6z,(g f9 b0$^{\circ} C$ 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 al7mmsi5b.2k k tuminum rod of the same length and cross-sectional area are attached end to enbt5.s2mk 7mk id (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 i; yovl-1o1sjm-gv*w the whole Earth receives energy from the Somv1s;- jwyio- 1vl g*un.    $ \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 generatesfc6ndtayp 4t5 bq k- (+5z)uve 95 W of heat, which is dissipated through a glass bulb that has a radius of 3.0 cm and is 1.0 mm t +q5(6tp z 4kbyndat5)vc-eufhick. 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 come mainly from a 4.)7 2qdt smrfx10-in. layer of brick and an R-19 layer of insulationf1s xdq27tm r), as shown in 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 u srpp gugd(2y gf)ky(y21-a9 panes of glass separated by an air space, Fig. 14–20. (a) Show that the ratyy fgsy2-(r d)1p2 k(9gguua pe of heat flow through such 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: bl;5divob3i62e3e n itt th* 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 contains a/ci /d-p bh;o/gui4s:gjd4fsbout 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 o+jgq( 29a)weu g6 mpxnceans, estimate the heat liberated when a cube of ocep( n jgqegxau2+w)96m an 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 tested by firing it into a fixed block of wood with a m+c4b4cnxd 5 tl)fogcy+ tt),i ass of 1.05 kg. The block and imbedded bullet together absorb all the heat generated. After thermal equilibrium has been , +dttonb4li )gctc +)cxy5f4reached, 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, assuming it jzj. beqr 3,ed2 8h(wtto be a perfect emitter at .h(,ejtb2er8 3 wqzjd$T\,=\,5500K$ 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 pssov 3qth+ 5leh 8r(e0erson 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 falls 6rsmabq. k8r:zaa 2m. a vertical height of 140 m before striking the ground. Estimate the temperature rise of the ro:z kbs 8r2m.r6a.qaamck 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 pai gzl3x7*txzw82 ei6np5u)o hsl of water initially at 25zx pehzo)gu62x nlwi s83t*7 0.0$^{\circ} C$. 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 thicbp3x kxv4s wtd,* f6b6k with total surface are bsx6dv* k4t,fxb6p3wa $1.2\,m^2$ 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 h*t pigeuf24 //rem;6 8 ldczean 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 y9 1jsck1jb5qj ;hr81lds 5zi of the body to the surface. Assume that the thickness o519hqbldj8jy15r i jk s 1;zcsf 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 os8br.dsd4// py y6iyj:mg)o 2o czm9g f air) and ar82o rosbcz./4d9p6 gi md:jg )ys/my yea $410\,m^2$ 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 ucsrws p3+vr,-* *uxff/fg0 eat $220\,m/s$ 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 ip mr s m:l2hct ..,sb(l6zh4b(a) in Problem 58, take into account radiation from the leaf to calculate how much water must be transpired (evaporatec( zsrllbh2p,.6hbm m:. ti s4d) by the leaf per hour to maintain a temperature of 35$^{\circ} C$.    g/h

  An iron meteorite mel8 ez7h4n0md; by5+ pd-fu+ mupc+o icsts when it enters the Earth’s atmosphere. If its initial temperature was -ucbn p+8c4m 0 eysz+ 5po hf-m+u;7did125$^{\circ} C$ 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 Eart .;2m3hjmy1ff kffzzw:) xp7e h’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 people hit a s kdnedyu m0grpk3pm 4 .j zq3u4miq(b)6 ed969oft rubber ball at a wall until they are about to drop due to dehydration and ejkmg9eunq)qy dbep4k m664 pzd id3( r.03u9mxhaustion. 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 result4 l65yd; hzyd e5lx*ke 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 conductio7rjn;w 57nntdnifwi :t-my0 +n and radiation at a rate of about 200 W. Estimate how loi rn0wt-7dn;wnj itm :fy 5+n7ng 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 dishwash67 h vf,rm pwm6.r*zvming, there is “no hot water” left in the 50-gal (185-L) water heater.f v z 6mwv*hmmpr6r7,. 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 thege 1 m,m*ddrh/ glass surface of a 60-W lightbulb is 65$^{\circ} C$ when the room temperature is 18$^{\circ} $C. Estimate the temperature of a 150-W lightbulb with a glass bulb the same size. Consider only radiation, and assume that 90% of the energy is emitted as heat.    $^{\circ} C$