Phys 111 Final Exam December 12, 2016 - Iowa State Universitycourses.physics.iastate.edu/phys111/exams/Exam...Phys 111 Final Exam December 12, 2016 ... 66. A batter hits a 0.140-kg

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Phys 111 Final Exam December 12, 2016

Name_____________________________ Section_______ University ID___________________

Please fill in your computer answer sheet as follows:

1) Use your previous answer sheet and start with 61. Note problem number of the final exam starts

with 61.

2) Make sure that you filled in the circles on the sheet corresponding to the letters or numbers of your

name, ID and section.

3) If you use a new answer sheet, follow the following instruction.

4) Fill in the circles on the sheet corresponding to the letters or numbers of your name, ID and section

with a #2 pencil.

5) In the NAME grid, fill in your last name, leave one blank space, then your first name.

6) Write your ID number in the IDENTIFICATION NUMBER section of the sheet.

7) Write your recitation section number in the spaces K, L in the SPECIAL CODES section. Single

digits should be preceded by a 0 (e.g. section 1 is written as 01).

_____________________________________________________________________________________

GOOD LUCK ON THE FINAL EXAM

Unless otherwise specified in a problem:

g = 9.81 m/s2

Universal gravitational constant G = 6.67×10-11

N･m2/kg

2

Atmospheric pressure = 1.01 × 105 Pa

Density of water = 1000 kg/m3

specific heat of water = 4186 J/(kg･K)

Gas constant R = 8.31 J/(mol･K)

0 K = -273 ℃

2

61. In the year 2000, the average size of a transistor in a microprocessor was 250 nanometers.

A human hair has a diameter of 70 microns (micrometers). How many transistors fit across a

human hair? (1 nanometer = 10-9

meter, 1 micrometer = 10-6

m)

A) 2800

B) 280

C) 28

D) 2.8

E) 0.28

______________________________________________________________________________

62. Refer to the above figure. Vector T as expressed in terms of vectors M and N is given

by

A) M + N .

B) M - N .

C) M .

D) N .

E) None of the other choices is correct.

63. An airplane starts from rest and accelerates at 10.8 m/s2. What is its speed at the end of a

400 m-long runway?

A) 37.0 m/s

B) 93.0 m/s

C) 65.7 m/s

D) 4320 m/s

E) 186 m/s

______________________________________________________________________________

64. A bullet is fired with a certain velocity at an angle θ above the horizontal at a location.

The initial x and y components of its velocity are 86.6 m/s and 49.1 m/s respectively. How

long does it take before the bullet gets to the highest point of its trajectory?

A) 5.0 seconds

B) 10.0 seconds

C) 15.0 seconds

D) 20.0 seconds

E) None of the other choices is correct.

3

m1

m2

m

3

F

65. A catcher stops a ball traveling at 40 m/s in a distance of 20 cm and feels a force of 600 N

against his glove. What is the mass of the ball?

A) 0.10 kg

B) 0.15 kg

C) 0.20 kg

D) 0.25 kg

E) 0.30 kg

_____________________________________________________________________

66. A batter hits a 0.140-kg baseball that was approaching him at 40.0 m/s and, as a result,

the ball leaves the bat at 20.0 m/s in the direction of the pitcher. What is the magnitude of the

impulse delivered to the baseball?

A) 9.80 Ns

B) 1.40 Ns

C) 5.60 Ns

D) 4.90 Ns

E) 8.40 Ns

_____________________________________________________________________

67. Pulling up on a rope, you lift a 4.35-kg bucket of water from a well with an acceleration

of 1.78 m/s2. What is the tension in the rope?

A) 0 N

B) 7.74 N

C) 34.9 N

D) 42.7 N

E) 50.4 N

_____________________________________________________________________

68. A locomotive is pulling three wagons along a level track with a force of F=100,000 N.

The wagon next to the locomotive has a mass of m1=80,000 kg, the next one, m2=50,000 kg,

and the last one, m3=70,000 kg. Neglect friction. What is the force between the 50,000-kg

and 70,000-kg wagons?

A) 35,000 N

B) 40,000 N

C) 50,000 N

D) 60,000 N

E) 65,000 N

4

69. Swimmers at a water park have a choice of two frictionless water slides (see the above

figure). Although both slides drop over the same height, h, slide 1 is straight while slide 2 is

curved, dropping quickly at first and then leveling out. How does the speed v1 of a swimmer

reaching the end of slide 1 compares with v2, the speed of a swimmer reaching the end of

slide 2?

A) v1 > v2

B) v1 < v2

C) v1 = v2

D) No simple relationship exists between v1 and v2.

70. A 2.0-g bead slides along a wire, as shown in the figure above. At point A, the bead is at

rest. Neglect friction and use g = 10 m/s2. What is the speed of the bead at point C?

A) 0 m/s

B) 1.0 m/s

C) 2.0 m/s

D) 4.0 m/s

E) There is not enough information to solve this problem.

5

71. Two ice skaters push off against one another starting from a stationary position. The 45-

kg skater acquires a speed of 0.375 m/s. What speed does the 60-kg skater acquire?

A) 0.500 m/s

B) 0.281 m/s

C) 0.375 m/s

D) 0.750 m/s

E) 0 m/s

72. Find the x coordinate of the center of mass

of the bricks shown in the right figure.

A) L

B) 0.5L

C) 1.5 L

D) 0.92 L

E) 1.1 L

73. The moment of inertia of a uniform rod (about its center) is given by I = ML2/12. What is

the kinetic energy of a 120-cm rod with a mass of 450 g rotating about its center at 3.60

rad/s?

A) 0.350 J

B) 4.20 J

C) 0.700 J

D) 0.960 J

E) 2.10 J

74. The mass of the Moon is 7.4 × 1022 kg and its mean radius is 1.75 × 103 km. What is

the acceleration due to gravity at the surface of the Moon?

A) 2.8 × 106 m/s2

B) 9.8 m/s2

C) 4.9 m/s2

D) 1.6 m/s2

E) 0.80 m/s2

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75. An 82.0 kg-diver stands at the edge of a light 5.00-m diving board, which is supported

by two pillars 1.60 m apart, as shown in the figure above. Find the force exerted by pillar B.

A) 1.71 kN downwards

B) 1.71 kN upwards

C) 2.51 kN downwards

D) 2.51 kN upwards

E) 3.44 kN upwards

76. The frequency of the standing wave in a pipe (both ends open) shown in the right figure

is 202 Hz. What is the fundamental frequency of the pipe?

A) 50.5 Hz

B) 101 Hz

C) 151 Hz

D) 252 Hz

E) 303 Hz

77. A piece of wood with density of 706 kg/m3

is tied with a string to the bottom of a water-

filled flask (see the right figure). The wood is

completely immersed, and has a volume of

8.00×10-6

m3. What is the tension in the string?

The density of water is 1000 kg/m3.

A) 0.0554 N

B) 0.0785 N

C) 0.133 N

D) 0.0231 N

E) 0.101 N

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78. A mass of 0.150 kg is attached to a spring with a force constant of 3.58 N/m and

undergoes simple harmonic oscillations. What is the period of the oscillations?

A) 2.57 s

B) 0.527 s

C) 0.263 s

D) 1.14 s

E) 1.29 s

79. In a section of horizontal pipe with a diameter of 4.00 cm the pressure is 95 kPa and

water is flowing with a speed of 1.25 m/s. The pipe narrows to 2.00 cm and speeds up to 4.25

m/s. What is the pressure in the narrower region? (Density of water is 1000 kg/m3)

A) 95.0 kPa

B) 43.7 kPa

C) 116.7 kPa

D) 86.8 kPa

E) 77.7 kPa

80. On a cold day, you take in 4.2 L of air into your lungs at a temperature of 0°C. If you

hold your breath until the temperature of the air in your lungs reaches 37°C, what is the

volume of the air in your lungs at that point, assuming the pressure does not change?

A) 4.2 L

B) 4.4 L

C) 4.6 L

D) 4.8 L

E) 5.0 L

81. How much heat must be removed from 456 g of water at 25.0°C to change it into ice at

-10.0°C? The specific heat of ice is 2090 J/(kg K) and the latent heat of fusion of water is

33.5 × 104 J/kg.

A) 105 kJ

B) 153 kJ

C) 57.3 kJ

D) 47.7 kJ

E) 210 kJ

8

82. A solid concrete wall 4.0 m by 2.4 m and 30 cm thick, with a thermal conductivity of 1.3

W/(m∙K), separates a basement at 18°C from the ground outside at 6°C. How much heat

flows through the wall in one hour?

A) 1.8 MJ

B) 1.8 kJ

C) 500 J

D) 5.0 MJ

E) 5.0 kJ

83. Two metal rods, one silver and the other copper, are both attached to a steam chamber,

with a temperature of 100°C, at one end, and an ice water bath, with a temperature of 0°C, at

the other. The rods are 5.0 cm long and have a square cross-section, 2.0 cm on a side. How

much heat flows through the two rods in 60 s? The thermal conductivity of silver is 417

W/(m·K), and that of copper is 395 W/(m·K). No heat is exchanged between the rods and

the surroundings, except at the ends.

A) 20 kJ

B) 39 kJ

C) 47 kJ

D) 49 kJ

E) 11 kJ

84. What is the net power that a dog with surface area of 0.075 m2 radiates if his emissivity

is 0.75, his skin temperature is 315 K, and he is in a room with a temperature of 290 K? The

Stefan-Boltzmann constant is 5.67 x 10-8 W/(m2·K4).

A) 9.0 W

B) 6.0 W

C) 8.0 W

D) 15 W

E) 18 W

85. A gas expands from an initial volume of 0.040 m3 to a

final volume of 0.085 m3 while its pressure increases

linearly with the volume (so that the process follows a

straight-line path in a P-V diagram as typically shown in the

right figure) from 110 kPa to 225 kPa. How much work is

done by the system?

A) 5.2 kJ

B) 7.5 kJ

C) 7.8 kJ

D) 11 kJ

E) 12 kJ

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86. An ideal gas absorbs 750 J of heat as it performs 625 J of work. What is the resulting change

in temperature if there are 1.3 moles of an ideal gas in the system? [Gas constant R = 8.31 J/(mol

K)]

A) 84.8 K

B) 0 K

C) 11.6 K

D) 127 K

E) 7.7 K

87. In the closed thermodynamic cycle shown in the P-V diagram, the work done by the

gas is:

A) 0

B) positive

C) negative

D) cannot be determined

88. A gasoline engine with an efficiency of 0.40 generates 1500 W (= J/s) of power. If a liter of

gasoline has an energy content of 3.7 x 107 J, how many liters of gasoline does the engine

consume each hour?

A) 0.15 liters

B) 0.21 liters

C) 0.36 liters

D) 0.42 liters

E) 0.48 liters

V

P

10

89 . An ideal monatomic gas undergoes the reversible expansion shown in the above figure,

where V2 = 4V1 and P2 = 2P1. What is the change in internal energy of the gas in this

process, in terms of the initial pressure and volume?

A) 2.5 P1V1

B) 5 P1V1

C) 10.5 P1V1

D) 21 P1V1

E) 27.5 P1V1

90. What is the change in entropy when 15.0 g of water at 100°C are turned into steam at 100°C?

The latent heat of vaporization of water is 22.6 × 105 J/kg.

A) 90.8 J/K

B) -90.8 J/K

C) 339 J/K

D) -339 J/K

E) 0 J/K

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Record Sheet of Final Exam, Physics 111, Fall 2016

You may fill in this sheet with your choices and take it with you for comparison to the posted

answers.

61 71 81

62 72 82

63 73 83

64 74 84

65 75 85

66 76 86

67 77 87

68 78 88

69 79 89

70 80 90

Physics 111, Fall 2016: Formula sheet

Vectors:

cosxA A sinyA A 2 2

x yA A A 1tan /y xA A

Linear Motion:

f ix x x /v x t /a v t 0v v a t

2

0

1

2x v t a t 2 2

0 2v v a x 0

1

2x v v t

Forces:

1 2 3

1

N

net i

i

F F F F F

netFa

m 1 2

2g

m mF G

r

Weight W mg k kf N s sf N xF kx

_____________________________________________________________________________

Work and Energy:

( cos )W F d 2 / 2KE mv

PE mgh

2 / 2PE kx

/ /P work t Fd t Fv

totE KE PE

Linear momentum and impulse:

p mv F t p I F t p 0 f ip p p

/cm i i ix m x m /cm i i iy m y m

Uniform Circular Motion:

2 /v r T 2 /ca v r

2 /cF mv r 2tan /v rg

Rotational Kinematics:

/s r / t / t 0 t 2 /T

2

0

1

2t t

2 2

0 2 tv r t r 2

ca r

Rotational Dynamics:

sinr F 2

i iI m r /I L t L I

0 f iL L L

2 / 2RKE I W

Gravity: 2

1 2 /gF Gm m r 11 2 26.67 10 /G Nm kg 1 2 /gPE U Gm m r

2 / 2KE mv

Oscillations about equilibrium:

22 f

T

F kx

2cos( ); sin( ); cos( )x xx A t v A t a A t

k

m

2 2 21 1 1

2 2 2E KE PE mv kx kA 2

LT

g

Waves and Sound:

v fT

;

F mv

L

24

P PI

A r

12 2

0 0(10 )log( / ); 10 /dB I I I W m

log( ) log( ) log( );AB A B log( / ) log( ) log( ); log(10 )nA B A B n

Doppler Effect for moving source: 0

1

1 /s

s

f fv v

(-) source moving towards observer

Doppler Effect for moving observer: 0

0 1s

vf f

v

(+) observer moving towards source

Constructive Interference: 1 2 ; 0,1,2,3,...d d n n

Destructive Interference: 1 2 ; 1,3,5,...2

d d n n

Standing waves on a string of length L = Standing waves in a column of air open at both ends of length L

2; ; 1,2,3,...

2n n

n

L v vf n n

n L

Standing waves in a column of air closed at one end of length L

4; ; 1,3,5,...

4n n

n

L v vf n n

n L

Beat Frequency: 1 2beatf f f

Fluids:

5 2; ; ; 1.01 10 /gauge atm atm

M FP P P P P N m

V A

2 1P P gh

Buoyant fluidF Vg

1 21 1 1 2 2 2:

m mConversation of Mass Av A v

t t

2 2

1 1 1 2 2 2

1 1' :

2 2Bernoulli s Equation P v gy P v gy

Temperature and Heat:

0 0

532 273.15; ; ;

9C F K CT T T T L L T V V T Q mc T

4 8 2 4; ; / / ; / ; 5.67 10 ( )fusion f vaporization vQ mL Q mL Q t kA T L Q t e AT W m K

Ideal Gases: 23; / / ( ); 8.31 ( ); 1.38 10 /B A BPV nRT Nk T n N N m mass per mole R J mol K k J K

23 21 3 3 36.02 10 / ; ( ) ;

2 2 2 2A av av B BN molecules mole KE mv k T U nRT Nk T

Thermodynamics:

; ; 3 / 2; 5 / 2; / 5 / 3V P P VU Q W W P V C R C R C C

1 1 ; ;h c c c h c

h h h h

Q Q Q T Q QWe COP Air Conditioner COP

Q Q Q T W W

; 0h ctotal

h c

Q QQS S

T T T