Deck 14: Sound: Part A

Question 1

An inventor develops a stationary cycling device by which an individual,while pedaling,can convert all of the energy expended into heat for warming water.What minimum power must be generated if 300 g of water (enough for 1 cup of coffee)is to be heated in 10 min from 30°C to 90°C? (1 cal = 4.186 J,the specific heat of water is 4 186 J/kg · °C)

A) 9400 W
B) 590 W
C) 160 W
D) 130 W

Answer 1

130 W

Question 2

Marc attaches a falling 250-kg object with a rope through a pulley to a paddle wheel shaft.He places the system in a well-insulated tank holding 12 kg of water.When the object falls,it causes the paddle wheel to rotate and churn the water.If the object falls a vertical distance of 100 m at constant speed,what is the temperature change of the water? (1 kcal = 4186 J,the specific heat of water is 4186 J/kg · °C,and g = 9.8 m/s²)

A) 19,600°C
B) 4700°C
C) 4.9°C
D) 2.3°C

Answer 2

4.9°C

Question 3

A substance is heated from 15°C to 45°C.What would the same incremental change be when registered in kelvins?

A) 20
B) 40
C) 30
D) 313

Answer 3

30

Question 4

133°F is how many degrees Celsius?

A) 31
B) 49
C) 56
D) 158

Question 5

If a 2100-kg car was moving at 30 m/s,what would be its kinetic energy expressed in the unusual (for kinetic energy)units of calories? (1 cal = 4.186 J)

A) 3.0 × 10⁴
B) 2.3 × 10⁵
C) 3.8 × 10⁶
D) 1.1 × 10⁵

Question 6

A 20-kg piece of aluminum (which has a specific heat of 900 J/kg · °C)is warmed so that its temperature increases by 5.0°C.How much heat was transferred into it?

A) 4.5 × 10⁴ J
B) 9.0 × 10⁴ J
C) 1.4 × 10⁵ J
D) 2.0 × 10⁵ J

Question 7

A 3.00 g lead bullet is traveling at a speed of 300 m/s when it embeds in a wood post.If we assume that half of the resultant heat energy generated remains with the bullet,what is the increase in temperature of the embedded bullet? (specific heat of lead = 0.0305 kcal/kg· °C,1 kcal = 4186 J)

A) 113°C
B) 137°C
C) 176°C
D) 259°C

Question 8

A waterfall is 70 m high.What is the increase in water temperature at the bottom of the falls if all the initial potential energy goes into heating the water? (g = 9.8 m/s²,c_w = 4186 J/kg·°C)

A) 0.16°C
B) 0.34°C
C) 0.69°C
D) 1.04°C

Question 9

A machine gear consists of 0.40 kg of iron and 0.16 kg of copper.How much total heat is generated in the part if its temperature increases by 35°C? (Specific heats of iron and copper are 450 and 390 J/kg · °C,respectively. )

A) 910 J
B) 8500 J
C) 4000 J
D) 5300 J

Question 10

A swimming pool heater has to be able to raise the temperature of the 30,000 gallons of water in the pool by 10.0°C.How many kilowatt-hours of energy are required? (One gallon of water has a mass of approximately 3.79 kg and the specific heat of water is 4186 J/kg · °C. )

A) 1960 kWh
B) 1320 kWh
C) 1130 kWh
D) 216 kWh

Question 11

A temperature change from 15°C to 45°C corresponds to what incremental change in °F?

A) 54
B) 40
C) 36
D) 313

Question 12

If it is given that 546 K equals 273°C,then it follows that 423 K equals:

A) 127°C.
B) 150°C.
C) 473°C.
D) 1200°C.

Question 13

A 0.2-kg aluminum plate,initially at 20°C,slides down a 10-m long surface,inclined at a 30° angle to the horizontal.The force of kinetic friction exactly balances the component of gravity down the plane so that the plate,once started,glides down at constant velocity.If 90% of the mechanical energy of the system is absorbed by the aluminum,what is its temperature increase at the bottom of the incline? (Specific heat for aluminum is 900 J/kg · °C. )

A) 0.16°C
B) 0.07°C
C) 0.05°C
D) 0.03°C

Question 14

An inventor develops a stationary cycling device by which an individual,while pedaling,can convert all of the energy expended into heat for warming water.How much mechanical energy is required to increase the temperature of 300 g of water (enough for 1 cup of coffee)from 30°C to 90°C? (1 cal = 4.186 J,the specific heat of water is 4186 J/kg · °C)

A) 94,000 J
B) 75,000 J
C) 5400 J
D) 14 J

Question 15

Arrange the temperatures 40 ºF,40 ºC,and 40 K from highest to lowest.

A) 40 ºF,40 ºC,40 K
B) 40 ºC,40 K,40 ºF
C) 40 ºF,40 K,40 ºC
D) 40 ºC,40 ºF,40 K

Question 16

A solar heated house loses about 7.4 × 10⁷ cal through its outer surfaces on a typical 24-hour winter day.What mass of storage rock is needed to provide this amount of heat if it is brought up to initial temperature of 62°C by the solar collectors,and the house is maintained at 20°C? (Specific heat of rock is 0.21 cal/g · °C. )

A) 160 kg
B) 1200 kg
C) 6100 kg
D) 8400 kg

Question 17

Arrange the following units,Calorie,calorie,and Joule from smallest to largest.

A) Joule,Calorie,calorie
B) calorie,Calorie,Joule
C) Joule,calorie,Calorie
D) Answers a and c are both correct,it apparently is a trick question.

Question 18

A piece of copper of mass 100 g is being drilled through with a ¹/₂" electric drill.The drill operates at 50.0 W and takes 30.0 s to bore through the copper.If all the energy from the drill heats the copper,find the copper's increase in temperature.(c_copper = 387 J/kg · °C. )

A) 40.6°C
B) 38.8°C
C) 31.0°C
D) 27.3°C

Question 19

A solar heating system has a 25.0% conversion efficiency;the solar radiation incident on the panels is 1000 W/m².What is the increase in temperature of 40.0-kg of water in a 1.00-h period by a 4.00 m² area collector? (c_w = 4186 J/kg · °C)

A) 14.3°C
B) 21.5°C
C) 28.7°C
D) 44.3°C

Question 20

What is the temperature increase of 3.0 kg of water when heated by an 800-W immersion heater for 10 min? (c_w = 4186 J/kg · °C)

A) 56°C
B) 38°C
C) 29°C
D) 14°C

Question 21

I take 2.0 kg of ice and dump it into 1.0 kg of water and,when equilibrium is reached,I have 3.0 kg of ice at 0°C.The water was originally at 0°C.The specific heat of water = 1.00 kcal/kg·°C,the specific heat of ice = 0.50 kcal/kg·°C,and the latent heat of fusion of water is 80 kcal/kg.The original temperature of the ice was:

A) one or two degrees below 0°C.
B) −80°C.
C) −120°C.
D) The whole experiment is impossible.

Question 22

100 g of liquid nitrogen at its boiling point of 77 K is stirred into a beaker containing 600 g of 15°C water.If the nitrogen leaves the solution as soon as it turns to gas,how much water freezes? The heat of vaporization of nitrogen is 48 cal/g and that of water is 80 cal/g.

A) none
B) 29 g
C) 68 g
D) 109 g

Question 23

Which of the following has the highest specific heat?

A) ice
B) water
C) steam
D) They are all water,so they all have the same specific heat.

Question 24

A 6-g lead bullet traveling in 20°C air at 300 m/s strikes a flat steel plate and stops.What is the final temperature of the lead bullet? (Assume the bullet retains all heat. )The melting point of lead is 327°C.The specific heat of lead is 0.128 J/g·°C.The heat of fusion of lead is 24.5 J/g.

A) 227°C
B) 260°C
C) 293°C
D) 327°C

Question 25

A brass cube,10 cm on a side,is raised in temperature by 150°C.The coefficient of volume expansion of brass is 57 × 10−⁶/°C.By what percentage is any one of the 10-cm edges increased in length?

A) 4%
B) 2.8%
C) 0.38%
D) 0.29%

Question 26

A 50-g cube of ice,initially at 0.0°C,is dropped into 200 g of water in an 80-g aluminum container,both initially at 40°C.What is the final equilibrium temperature? (Specific heat for aluminum is 900 J/kg·°C,the specific heat of water is 4186 J/kg·°C,and L_f = 3.33 × 10⁵ J/kg. )

A) 17.6°C
B) 9.5°C
C) 12.1°C
D) 20.6°C

Question 27

A slice of bread contains about 90 kcal.If specific heat of a person were 1.00 kcal/kg·°C,by how many °C would the temperature of a 70.0-kg person increase if all the energy in the bread were converted to heat?

A) 2.25°C
B) 1.86°C
C) 1.43°C
D) 1.29°C

Question 28

A brass cube,10 cm on a side,is raised in temperature by 150°C.The coefficient of volume expansion of brass is 57 × 10−⁶/°C.By what percentage does volume increase?

A) 12%
B) 2.8%
C) 1.1%
D) 0.86%

Question 29

A 0.0030-kg lead bullet is traveling at a speed of 300 m/s when it embeds in a block of ice at 0°C.If all the heat generated goes into melting ice,what quantity of ice is melted? (L_f = 80 kcal/kg,the specific heat of lead = 0.03 kcal/kg·°C,and 1 kcal = 4186 J)

A) 1.47 × 10−² kg
B) 4.0 × 10−⁴ kg
C) 3.2 × 10−³ kg
D) 2.6 × 10−⁴ kg

Question 30

Find the final equilibrium temperature when 20.0 g of milk at 10.0°C is added to 160 g of coffee at 90.0°C.(Assume the specific heats of coffee and milk are the same as water and neglect the heat capacity of the container,and c_water = 1.00 cal/g·°C = 4186 J/kg·°C)

A) 85.3°C
B) 81.1°C
C) 71.4°C
D) 66.7°C

Question 31

When heating 2 kg of ice from -40°C,2 kg of water from 20°C to 50°C,and 2 kg of steam from 100°C to 125°C,which requires the most energy?

A) the ice
B) the water
C) The steam,it's obvious since it is the hottest.
D) All three take the same amount.

Question 32

A steel wire,100 m long at 10°C,has a coefficient of linear expansion of 11 × 10−⁶/°C.Give its change in length as the temperature changes from 10°C to 45°C.

A) 0.65 cm
B) 3.8 cm
C) 5.8 cm
D) 12 cm

Question 33

A puddle holds 150 g of water.If 0.75 g of water evaporates from the surface,what is the approximate temperature change of the remaining water? (L_v = 540 cal/g)

A) -2.7°C
B) +2.7°C
C) −0.27°C
D) +0.27°C

Question 34

Iced tea is made by adding ice to 3.0 kg of hot tea,initially at 80°C.How many kg of ice,initially at 0°C,are required to bring the mixture to 10°C? (L_f = 3.33 x 10⁵ J/kg,c_w = 4186 J/kg·°C)

A) 2.8 kg
B) 1.6 kg
C) 1.4 kg
D) 2.3 kg

Question 35

An 100-g piece of copper,initially at 295°C,is dropped into 250 g of water contained in a 300-g aluminum calorimeter;the water and calorimeter are initially at 10.0°C.What is the final temperature of the system? (Specific heats of copper and aluminum are 0.0920 and 0.215 cal/g·°C,respectively.c_w = 1.00 cal/g·°C)

A) 12.8°C
B) 16.5°C
C) 18.1°C
D) 32.1°C

Question 36

How much heat energy must be removed from 150 g of oxygen at 22°C to liquefy it at −183°C? (The specific heat of oxygen gas is 0.218 cal/g·°C,and its heat of vaporization is 50.9 cal/g. )

A) 14,300 cal
B) 9560 cal
C) 4320 cal
D) 2160 cal

Question 37

A rectangular steel plate with dimensions of 60 cm × 25 cm is heated from 20°C to 150°C.What is its change in area? (Coefficient of linear expansion for steel is 11 × 10−⁶/°C. )

A) 0.82 cm²
B) 1.1 cm²
C) 4.3 cm²
D) 6.6 cm²

Question 38

A 100-g block of copper is taken from a kiln and quickly placed into a beaker of negligible heat capacity containing 300 g of water.The water temperature rises from 15°C to 40°C.Given c_Cu = 0.10 cal/g·°C,and c_water = 1.00 cal/g·°C,what was the temperature of the kiln?

A) 500°C
B) 635°C
C) 790°C
D) 535°C

Question 39

In typical calorimetry problems,what is the usual conservation law being used?

A) energy
B) heat
C) temperature
D) None since nothing is being conserved.

Question 40

A hot (70°C)lump of metal has a mass of 250 g and a specific heat of 0.25 cal/g·°C.John drops the metal into a 500-g calorimeter containing 40 g of water at 20°C.The calorimeter is constructed of a material that has a specific heat of 0.10 cal/ g·°C.When equilibrium is reached,what will be the final temperature? (c_water = 1.00 cal/g·°C. )

A) 114°C
B) 72°C
C) 40°C
D) 37°C

Question 41

Suppose working outside on a hot day someone generate 450 J of heat each second.If this energy is compensated for by the evaporation of sweat,how much water would be lost in an hour? The latent heat of fusion for water is 334 kJ/kg and for vaporization is 2,200 kJ/kg.

A) 4.85 liter
B) 0.74 liter
C) 0.50 liter
D) 1.5 liter

Question 42

In the text there is a table of coefficients of linear (α)and volume (β)expansions due to temperature changes.For the solid materials in this list,there is a relationship between α and β which allows you to find the value of β if you know α.Which of the following best describes that relationship?

A) α = β³
B) 3α = β
C) α = 3β
D) α³ = β

Question 43

A metal bar is used to conduct heat.When the temperature at one end is 100°C and at the other is 20°C,heat is transferred at a rate of 32 J/s.The bar is then stretched uniformly to twice its original length.If again it has ends at 100°C and 20°C,at what rate will heat be transferred between it ends?

A) 4 J/s
B) 8 J/s
C) 16 J/s
D) 32 J/s

Question 44

At 20°C an aluminum ring has an inner diameter of 5.000 cm,and a brass rod has a diameter of 5.020 cm.Keeping the brass rod at 20°C,which of the following temperatures of the ring will allow the ring to just slip over the brass rod? (α_Al = 2.4 × 10−⁵ /°C,α_brass = 1.9 × 10−⁵/°C )

A) 111°C
B) 187°C
C) 228°C
D) 437°C

Question 45

A silver bar of length 30 cm and cross-sectional area 2.0 cm² is used to transfer heat from a 100°C reservoir to a 0°C block of ice.How much ice is melted per second? (For silver,k = 427 W / m · °C.For ice,L_f = 334,000 J/kg. )

A) 4.2 g/s
B) 0.085 g/s
C) 0.80 g/s
D) 0.043 g/s

Question 46

A metal bar is used to conduct heat.When the temperature at one end is 100°C and at the other is 20°C,heat is transferred at a rate of 16 J/s.If the temperature of the hotter end is reduced to 60°C,what will be the rate of heat transfer?

A) 4 J/s
B) 8 J/s
C) 9 J/s
D) 12 J/s

Question 47

Carly places one end of a steel bar in a Bunsen flame and the other end in an ice cube.By what factor is the rate of heat flow changed when the bar's cross-sectional area is tripled?

A) 0.33
B) 1/9
C) 3.0
D) 9.0

Question 48

Dmitri places one end of a copper rod in a heat reservoir and the other end in a heat sink.By what factor is the rate of heat flow changed when the temperature difference between the reservoir and sink is doubled?

A) 2.0
B) 1/2
C) 4.0
D) 1/4

Question 49

The inside of a house is at 20°C on an early morning when the temperature outside is 15°C.The next morning the inside temperature is the same,but the outside temperature is now 5°C.How much does the energy per unit time lost by conduction through the walls,windows,doors,etc. ,change for the house from the first morning to the second one.

A) Since the inside temperature stays the same,the loss is the same both days.
B) The loss reduces to 1/3.
C) The loss triples.
D) The loss increases by 5/278 since we need to use the Kelvin scale for this calculation.

Question 50

A pipe of length 10.0 m increases in length by 2.0 cm when its temperature is increased by 90°F.What is its coefficient of linear expansion?

A) 22 × 10^-6/°C
B) 17 × 10^-6/°C
C) 13 × 10^-6/°C
D) 40 × 10^-6/°C

Question 51

Suppose the ends of a 20-m long steel beam are rigidly clamped at 0°C to prevent expansion.The rail has a cross-sectional area of 15 cm².What force does the beam exert when it is heated to 40°C? (α_steel = 1.1 × 10−⁵/C°,Y_steel = 2.0 × 10¹¹ N/m²)

A) 2.6 × 10⁵ N
B) 5.6 × 10⁴ N
C) 1.3 × 10⁵ N
D) 6.5 × 10² N

Question 52

I place a 250-g ice cube (initially at 0°C)in a Styrofoam box with wall thickness 1.0 cm and total surface area 600 cm².If the air surrounding the box is at 20°C and after 2 hours the ice is completely melted,what is the conductivity of the Styrofoam material? (L_f = 80 cal/g)

A) 9.6 × 10−⁵

B) 2.8 × 10−⁶

C) 1.15 × 10−²

D) 2.3 × 10−⁴

Question 53

A long steel beam has a length of fifty meters on a cold day when the temperature is 0°C.What is the length of the beam on a hot day when T = 40°C? (α_steel= 1.1 × 10−⁵/°C)

A) 50.044 m
B) 50.022 m
C) 50.088 m
D) 50.0044 m

Question 54

A steel piano string is attached,under tension,at each end to secure posts.When gently struck,a faint note can be detected coming from the string.The string is then cooled by blowing cold air over it and then is struck again.How does the note now detected compare to the previous one.

A) It is the same since the posts don't move.
B) It is at a higher frequency than the original one.
C) It is at a lower frequency than the original one.
D) More than one answer is correct.

Question 55

A windowpane is half a centimeter thick and has an area of 2.0 m².The temperature difference between the inside and outside surfaces of the pane is 15°C.What is the rate of heat flow through this window? (Thermal conductivity for this glass is 0.84 W / m ·°C. )

A) 5000 J/s
B) 2500 J/s
C) 1300 J/s
D) 630 J/s

Question 56

An automobile gas tank is filled to its capacity of 20.00 gallons with the gasoline at an initial temperature of 10°C.The automobile is parked in the Sun causing the gasoline's temperature to rise to 60°C.If the coefficient of volume expansion for gasoline is 9.6 × 10−⁴/°C,what volume runs out the overflow tube? Assume the change in volume of the tank is negligible.

A) 1.74 gallons
B) 0.96 gallon
C) 0.72 gallon
D) 0.30 gallon

Question 57

As a copper wire is heated,its length increases by 0.200%.What is the change of the temperature of the wire? (α_Cu = 16.6 × 10−⁶/C°)

A) 120°C
B) 60.2°C
C) 30.1°C
D) 6.0°C

Question 58

A steel sphere sits on top of an aluminum ring.The steel sphere (α = 1.10 × 10−⁵/°C)has a diameter of 4.0000 cm at 0°C.The aluminum ring (α = 2.40 × 10−⁵/°C)has an inside diameter of 3.9900 cm at 0°C.Closest to which temperature given will the sphere just fall through the ring?

A) 462°C
B) 193°C
C) 116°C
D) 57.7°C

Question 59

A 2.00-kg copper rod is 40.00 cm long at 23°C.If 50,000 J are transferred to the rod by heat,what is its change in length? (c_copper = 387 J/kg·°C and α_copper = 17 × 10^-6/°C)

A) 0.022 cm
B) 0.044 cm
C) 0.055 cm
D) More information is needed.

Question 60

Two stars,A and B,have the same emissivity,but the radii and surface temperatures are different with R_A = 2 R_B,and T_A = 0.5 T_B.Assuming the temperature of space to be negligible,which star radiates the most energy per unit time?

A) Star A
B) Star B
C) Both radiate the same amount of energy per unit time.
D) More information is needed in order to make a determination.

Question 61

What temperature increase is necessary to increase the power radiated from an object by a factor of 16?

A) 8 K
B) 2 K
C) 100%
D) about 68%

Question 62

The Sun is a slightly variable star.What if the surface temperature of the Sun were to increase from 6000 K to 6100 K,what would be the increase in total power radiated assuming no other changes such as radius or emissivity?

A) 1.6%
B) 6.8%
C) 3.4%
D) 14%

Question 63

The filament temperature of a light bulb is 2000 K when the bulb delivers 50 W of power.If its emissivity remains constant,what power is delivered when the filament temperature is 2500 K?

A) 122 W
B) 62 W
C) 98 W
D) 50 W

Question 64

At high noon,the Sun delivers 900 W to each square meter of a blacktop road.What is the equilibrium temperature of the asphalt,assuming its emissivity e = 1? (σ = 5.67 × 10−⁸ W/m²×K⁴).

A) 75°C
B) 82°C
C) 91°C
D) 99°C

Question 65

The tungsten filament of a light bulb has an operating temperature of about 2100 K.If the emitting area of the filament is 0.80 cm²,and its emissivity is 0.68,what is the power output of the light bulb? (σ = 5.67 × 10−⁸ W/m² · K⁴)

A) 100 W
B) 75 W
C) 60 W
D) 40 W

Question 66

If the surface temperature of the Earth is 290 K and that of the Sun is 6000 K,assuming the same emissivities,what is the ratio of the energy radiated per square meter of the Earth to that of the Sun?

A) 0.48
B) 2.3 × 10^-3
C) 6.4 × 10^-5
D) 5.5 × 10^-6

Question 67

An object at 27°C has its temperature increased to 47°C.The power then radiated by this object increases by how many percent?

A) 3.3
B) 14
C) 29
D) 253