Iwasaki Hironori Physics 231c Final Exam

Hironori Iwasaki - PHY231, Fall 2012 - Introd
Final Exam - 2011
1
Solid bar (Pivot at end): IEND = 1/3 ML2
Another useful quantity:
Iwasaki
Hironori
iwasaki@msu
Physics 231c Final Exam
• Please keep this exam closed until instructed to begin.
• You will have 120 minutes to complete this exam.
• This exam is closed book and closed notes.
• You can use your calculator and three 8.5"x11" formula
sheets.
• Please use the blank space on the exam for your calculations.
• Exams and bubble sheets will be collected at the end
of the exam.
• Good Luck!
Useful Numbers:
G
=
6.67x10-11
3
2
m /kg/s
N A=
6.02x1023
/mole
R= 8.31 J/(moleK)
1 calorie= 4.1868 J
g = 9.81 m/s2
k B= 1.38x10-23 J/K
1 atm. = 1.013x105
N/m2
σ
=
5.67x10-8
2
4
w/m /K
Possibly Useful Moments of Inertia:
Solid homogeneous cylinder: ICM = 1/2 MR2
Solid homogeneous sphere: ICM = 2/5 MR2
Hoop (thin cylindrical shell: ICM = MR2
Solid bar (Pivot at C.M.): ICM = 1/12 ML2
Intensity threshold for hearing: I0 = 1x10
density of water: ρ=1000 kg/m3
-12
W/m2
Hironori Iwasaki - PHY231, Fall 2012 - Introd
Final Exam - 2011
3
T
Wpost
W
lamp
4 pt
A lamp hangs from end of a post whose weight is 334 N. If
the tension in the wire is 630 N, what is the weight of the
lamp? (in N)
1. A 49
E 215
B 70
C 102
D 148
F 311
G 451
H 654
4 pt A wooden statue is completely submerged in Lake
Michigan, but does not float to the surface due to a cable
mooring the statue to the floor of the lake. The weight of the
statue out of the water is W , the tension in the cable is T ,
and the buoyant force acting on the statue is B.
⊲ Defining upward as positive, the net force acting
on the statue (buoyant + gravitational + tension) is
_______________________ zero.
2. A CANNOT BE DETERMINED
B greater than
C less than
D equal to
⊲ The magnitude of B is ________________ the
magnitude of W .
3. A CANNOT BE DETERMINED
B greater than
C less than
D equal to
4 pt A truck horn emits a sound with a frequency of 237
Hz. The truck is moving on a straight road with a constant
speed. If a person standing on the side of the road hears the
horn at a frequency of 260 Hz, then what is the speed of the
truck? Use 340 m/s for the speed of the sound.
(in m/s)
4. A 3.01 × 101
D 4.34 × 101
G 6.26 × 101
B 3.40 × 101
C 3.84 × 101
E 4.90 × 101
F 5.54 × 101
H 7.08 × 101
Hironori Iwasaki - PHY231, Fall 2012 - Introd
Final Exam - 2011
5
4 pt A child slides down a frictionless playground slide from
a height of 2.1 m above the ground. If he starts with an initial
speed of 2 m/s and the end of the slide is 0.8 m above the
ground, her final speed will be: (in m/s)
5. A 5.43
E 10.18
B 6.36
C 7.44
D 8.70
F 11.91
G 13.93
H 16.30
6 pt
A puck of mass m=8 kg is attached by a string which passes
through a hole on a frictionless surface. The other end of the
string is held by a student. The puck initially slides on the
frictionless surface in a circular path of radius 7 m as shown
in the figure. The initial speed of the mass is 5 m/s. Then
the student pull on the string and reduces the radius to 3 m.
What is the final speed (in m/s)?
6. A 10.0
B 11.7
C 13.7
D 16.0
E 18.7
F 21.9
G 25.6
H 29.9
What is the final angular momentum (in Nm)?
7. A 63.3
E 280.0
B 91.8
C 133.2
D 193.1
F 406.0
G 588.7
H 853.6
Hironori Iwasaki - PHY231, Fall 2012 - Introd
Final Exam - 2011
7
5 pt
Consider the figure above, with M2= 4 kg and the static
coefficient of friction is 0.25. Imagine this table to be located
in a pressurized room on the moon, where the acceleration
due to gravity is 1.4 m/s2. What is the minimum value for
the mass, M1, in order that the block does not slide off the
table? (in kg)
(in kg)
8. A 3.62
E 16.00
B 5.25
C 7.61
D 11.03
F 23.20
G 33.64
H 48.78
5 pt
A boat heads directly across a river. Its speed relative to the
water is 2.7 m/s. It takes it 374 seconds to cross, but it ends
up 667 m downstream. How fast is the boat going relative to
the bank of the river?
(in m/s)
9. A 0.50
E 2.23
B 0.73
C 1.06
D 1.54
F 3.24
G 4.69
H 6.80
4 pt A steel wire in a piano has a length of 75 cm and a
mass of 9 g. To what tension must this wire be stretched in
order that the fundamental vibration correspond to middle C
(fC = 261.6 Hz on the chromatic musical scale)? (in N)
10. A 757 B 946 C 1183 D 1478
E 1848 F 2310 G 2887 H 3609
Hironori Iwasaki - PHY231, Fall 2012 - Introd
Final Exam - 2011
9
4 pt
35 g of water at 36 oC is mixed in an insulating cup with
100 g of water at 55 oC. Assume there is no exchange of
heat between the water and its surroundings and that the
water comes to thermal equilibrium with itself. The final
temperature of the water is _________. (in oC)
11. A 6.8
E 21.3
B 9.0
C 12.0
D 16.0
F 28.3
G 37.6
H 50.1
5 pt A 23.1 kg. boy skating in the positive x direction on a
frozen lake collides with a stationary 183.3 kg man. After the
collision, the boy moves at a velocity 2.25 m/s in the negative
x direction. The man ends up with a velocity of 0.914 m/s in
the positive x direction. What was the initial velocity of the
boy? (This collision is not elastic.) (in m/s)
12. A 5.000
D 9.766
G 19.073
B 6.250
C 7.812
E 12.207
F 15.259
H 23.842
4 pt Two marbles, one twice as heavy as the other, are
dropped (initial velocities are zero) to the ground from the
roof of a building. Just before hitting the ground, the kinetic
energy of the heavier marble is ___________ the kinetic
energy of the lighter marble.
⊲
13. A one fourth
B one half
C equal to
D twice
E four times
F impossible to determine
4 pt A projectile is launched at an angle of 35◦ above the
horizontal with a speed 93 m/s. At the highest point in its
trajectory, the vertical displacement above the ground is : (in
m)
14. A 26.2
E 82.0
B 34.8
C 46.3
D 61.6
F 109.0
G 145.0
H 192.9
4 pt
Two astronauts are tethered together on a space walk and
rotate around each other. They each weigh 67 kg and are 54
m apart. If the period of their rotation is 3.7 s, what is the
tension in the cable?
(in N)
15. A 709 B 943 C 1254 D 1667
E 2217 F 2949 G 3922 H 5217
Hironori Iwasaki - PHY231, Fall 2012 - Introd
Final Exam - 2011
11
7 pt
The figure above shows the path in the P-V plane that is
followed by a reversible Carnot engine that uses monatomic
Argon gas as its working substance. The system expands
isothermally from A to B, expands adiabatically from B to
C, contracts isothermally from C to D and contracts adiabatically from D to A.
⊲ Going along the path from A to B, the volume of the gas
_______.
16. A increases
B decreases
C stays the same
D cannot be determined
⊲ Going along the path from B to C, the pressure of the gas
_______.
17. A increases
B decreases
C stays the same
D cannot be determined
⊲ Going along the path from B to C, the internal energy of
the gas _______.
18. A increases
B decreases
C stays the same
D cannot be determined
⊲ Going along the path from B to C, heat flow
___________.
19. A goes into the gas
B goes out of the gas
C doesn’t occur
D cannot be determined
⊲ Going along the path from C to D, the internal energy of
the gas _______.
20. A increases
B decreases
C stays the same
D cannot be determined
⊲ Going along the cycle from D to A, The internal energy
____________.
21. A increases
B decreases
C remains the same
D cannot be determined
⊲ Going along the cycle from D to A, The gas
____________.
22. A does positive work
B does negative work
C does no work
D leaks out
Hironori Iwasaki - PHY231, Fall 2012 - Introd
Final Exam - 2011
13
12 pt
The figure above shows the path in the P-V plane that is
followed by a reversible Carnot engine that uses monatomic
Argon gas as its working substance and operates by taking
heat Qh = 4.1 kJ from a hot reservoir at Th = 1100 oC to do
work and deposits waste energy Qc into a cold reservoir at
Tc = 27 oC. At A, the Argon gas has a total internal energy
of 16 kJ. What is is its internal energy at B?
(in kJ)
23. A 16.0
B 21.3
C 28.3
E 50.1
F 66.6
G 88.6
What is the efficiency of this engine?
D 37.6
H 117.8
24. A 0.14
B 0.19
C 0.25
D 0.33
E 0.44
F 0.59
G 0.78
H 1.04
How much energy is deposited per cycle into the cold
reservoir?
(in kJ)
25. A 0.30
B 0.35
C 0.41
D 0.48
E 0.56
F 0.65
G 0.77
H 0.90
How many moles of Argon gas does the Carnot engine
contain?
26. A 0.45
B 0.51
C 0.57
D 0.65
E 0.73
F 0.83
G 0.93
H 1.06
If the gas occupies a volume of 0.0016 m3 at point A, what
it is the pressure at that point?
(in kPa)
27. A 1204 B 1602 C 2131 D 2834
E 3769 F 5013 G 6667 H 8867
Extra credit: What is the value for the area bounded by this
thermal cycle on the p-V diagram?
(in kJ)
28. A 3.20
E 10.02
B 4.26
C 5.67
D 7.54
F 13.33
G 17.73
H 23.58
Hironori Iwasaki - PHY231, Fall 2012 - Introd
Final Exam - 2011
15
3 pt What is the sound level of a sound with an intensity
of I = 1.00 × 10−6 W/m2? Give your answer in dB units.
29. A 48.00
D 93.75
G 183.11
B 60.00
C 75.00
E 117.19
F 146.48
H 228.88
3 pt Now the intensity of this sound is increased to a value of
32.0 times of its original intensity. What is the new increased
sound level? Give your answer in dB units.
30. A 40.05
D 64.15
G 102.74
B 46.86
C 54.83
E 75.05
F 87.81
H 120.20
4 pt An object with a mass of m = 3.25 kg is suspended
at rest between the ceiling and the floor by two thin vertical
ropes.
m
The magnitude of the tension in the lower rope is 17.8 N.
Calculate the magnitude of the tension in the upper rope.
(in N)
31. A 2.11 × 101
D 3.05 × 101
G 4.40 × 101
B 2.39 × 101
C 2.70 × 101
1
F 3.89 × 101
E 3.44 × 10
H 4.97 × 101
Hironori Iwasaki - PHY231, Fall 2012 - Introd
Final Exam - 2011
17
Hironori Iwasaki - PHY231, Fall 2012 - Introd
Final Exam - 2011
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