Download Practice final exam -all multiple choice

Spring 2013 - PHYS 2130 review for final exam – Answers will appear on Friday 04/26/13 on
last page
Review – 80 minutes, 30 questions (Actual final exam is 2 hours with 40-45 questions)
1. Displacement can be obtained from
A. the slope of an acceleration-time graph
B. the slope of a velocity-time graph
C. the area under an acceleration-time graph
D. the area under a velocity-time graph
2. The distance x traveled in time t by a car starting from rest is given by the expression
x=(1/2)at2 where a is a non-zero positive constant. What happens to the distance x when the time
t is tripled?
A.
B.
C.
D.
x increases by a factor of 3
x increases by a factor of 9/2
x increases by a factor of 9
x increases by a factor that depends on the value of a
3. A train car moves along a long straight track. The graph shows the position as a function of
time for the train.
position
time
The graph shows that the train:
A: speeds up all the time.
B: slows down all the time.
C: speeds up part of the time and slows down part of the time.
D: moves at constant velocity.
E: None of these statements is true.
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Spring 2013 - PHYS 2130 review for final exam – Answers will appear on Friday 04/26/13 on
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4. A compact car and a large truck collide head on and stick together. Which undergoes the
larger magnitude of momentum change?
A: car
B: truck
C: The magnitude of momentum change is the same for both vehicles.
D: Can’t tell without knowing the initial velocities.
Next two questions:
Two gliders with unequal mass (Mi < Mii) are on a frictionless air track.
You push horizontally, so the gliders move faster and
faster.
ii
5. How does the magnitude of the net force on glider i
compare with the magnitude of the net force on glider
ii?
i
FHand
No friction!
A) Fnet(i) > Fnet(ii)
B) Fnet(i) = Fnet(ii)
C) Fnet(i) < Fnet(ii)
6. Suddenly, you STOP pushing. (The gliders continue sliding along the track.) A few moments
later, what can you say about the net force on glider i?
A) Fnet(i) = 0
B) Fnet(i) is to the left
C) Fnet(i) is to the right
7. The vector A has length 5. The vector B has magnitude 4. You have no other information
about the two vectors. Which one of the following statements about the vector A+B is true?
A) The magnitude of the vector A+B must be between 5 and 9.
B) The magnitude of the vector A+B must be between 0 and 4.
C) The magnitude of the vector A+B must be between -1 and 9.
D) The magnitude of the vector A+B must be between 1 and 9.
8. An elevator is going down at a constant speed. On approaching its destination floor, it starts to
slow to a stop. During the period that it is slowing down, its acceleration is
A) downward.
B) upward.
C) in some other direction. D) zero
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Spring 2013 - PHYS 2130 review for final exam – Answers will appear on Friday 04/26/13 on
last page
9. A race car travels around the track shown at constant speed. Over which portion of the track
is the magnitude of the acceleration the largest?
2
4
3
1
A) From 1 to 2
C) Neither of these
B) From 3 to 4
D) Both of these
10. A block is held in place on a frictionless incline by a massless string, as shown. The string is
horizontal. Which figure best represents the force diagram ("free body diagram") for the block?
Block
A)
B)
C)
D)
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E)
Spring 2013 - PHYS 2130 review for final exam – Answers will appear on Friday 04/26/13 on
last page
11. A rock on a string is swinging in a vertical circle at constant speed. At the moment that the
rock is at the top of the swing, how does the magnitude of the tension in the string T compare
with the magnitude of the net force Fnet on the rock?
A) Fnet > T
B) Fnet < T
C) Fnet = T
12. The work done by a force F = (-3i + 10j) N on a particle that moves through a displacement
d = (16i - 12j) m is
A. 196 J
B. -124 J
C. -196 J
D. 160 J
E. None of the above
13. A spring-loaded dart gun shoots a dart straight up into the air, and the dart reaches a
maximum height of 24 m. The same dart is shot straight up a second time from the same gun,
but this time the spring is compressed only half as far before firing. How far up does the dart go
this time, neglecting friction and assuming an ideal spring?
A: 48m
B: 24m
C: 12m
D: 6m
E: 3m
14. Suppose a little calculator and a big physics text are sliding toward you on a frictionless air
table. Both have the same momentum, and you exert the same force to stop each. How do the
time intervals to stop them compare?
A: It takes less time to stop the little calculator.
B: Both take the same time.
C: It takes more time to stop the little calculator.
D: Impossible to tell without knowing actual masses of the calculator and the book.
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Spring 2013 - PHYS 2130 review for final exam – Answers will appear on Friday 04/26/13 on
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15. A bucket containing a brick is swung in a circle at constant speed in a vertical plane as
shown. The bucket is swung fast enough that the brick does not fall out.
The magnitude of the normal force is a minimum at position...
A) Top.
B) Bottom.
C) Right
D) The normal force has the same magnitude at all positions.
16. Particles a, b, c, d and e spin in a circle as shown in the figure.
The order of the centripetal accelerations for the particles is
A) d > e > c > a > b
B) e > a > b = c > d
C) b > e > a = c > d
D) b = e > d > a > c
E) None of these
17. A bicycle is redesigned such that the rims of the wheels are made lighter but more weight is
added to the frame so the total weight of the bike remains unchanged.
Compared to the old bike, when the new bike is moving at a given speed, its total kinetic energy
is..
A: less.
B: greater
C: the same.
D: not possible to determine without knowing the actual speed
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Spring 2013 - PHYS 2130 review for final exam – Answers will appear on Friday 04/26/13 on
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The following information is for the next two questions.
18. A disk and a hoop, both with the same mass M and the same radius R, both roll without
slipping with the same speed v, and are rolling toward an inclined plane, as shown.
Which object will roll up to the greatest height on the incline?
A) Disk
B) Hoop
C) same max height for both
D) Cannot determine without more information
19. Let the maximum vertical height reached by the hoop be Hhoop, and by the disk be Hdisk. The
ratio Hhoop / Hdisk is
A: 4/3
B: 3/4
C: 2/3
D: 3/2
E: 1
The following information is for the next two questions.
The period of a physical pendulum is T = 2  (I/mgL) ½, where I is the moment of inertia of the
pendulum (NOT about center of mass, but about the pivot point), and L is the distance between
the pivot and the center of mass of the pendulum. Compare the periods of two physical pendula.
One is a solid disk of mass m, radius R, supported at the edge. The other is a hoop of mass 4m,
radius R, supported at the edge.
pivot
C.M.
Disk
20. Which has the longer period?
A: Disk
B: Hoop
pivot
C.M.
Hoop
C: The periods are the same.
21. Let the period of oscillation of the hoop be Thoop, and the period for the disk be Tdisk. The
ratio Thoop / Tdisk is
A: √ ⁄
B: √ ⁄
C: 1
D: √3
E: none of these
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Spring 2013 - PHYS 2130 review for final exam – Answers will appear on Friday 04/26/13 on
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22. A star, assumed to be a uniform sphere, is rotating with a period T. There are no external forces
or torques acting on the star. Over a period of a million years, its radius decreases by a factor of 3.
What is the new period of the star?
(Hint: Isphere = (2/5)MR2 , and use conservation of angular momentum)
A) T/3
B) 3T
C) 9T
D) T/9
E) None of these.
23. A color TV of mass M is placed on a very light board supported at the ends, as shown. The
free-body diagram shows directions of the forces, but not their correct relative sizes.
What is the ratio FR/FL?
(Hint: consider the torque about the mass M).
FL
FR
M
(2/3)L
A: 2/3
B: 1/3
E: some other answer
Mg
L/3
C: 1/2
D: 2
24. A mass ‘m’ on a spring having spring constant ‘k’ oscillates with amplitude A and period T.
If the mass is tripled, and the amplitude of motion is doubled, what is the new period of
oscillation?
A: 3T
B: T/√3
C: T
D: √3 T
E: none of these
25. A mass ‘m’ on a spring having spring constant ‘k’ oscillates with amplitude A and period T.
If the mass is doubled, and the amplitude of motion is tripled, the total energy of the system…
A: stays the same
B: increases by a factor of 3
C: increases by a factor of 9/2
D: increases by a factor of 9
E: decreases by a factor of 2
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Spring 2013 - PHYS 2130 review for final exam – Answers will appear on Friday 04/26/13 on
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26. Three waves are traveling along identical strings (same linear density, same tension). Wave
B has twice the amplitude of the other two. Wave C has 1/2 the wavelength than A or B.
vwave
y
A
x
y
B
x
y
C
x
Which wave carries the least energy per time (power)?
A: A
B: B
C: C
D: More than two waves tie for minimum power
E: Need more information.
27. A string vibrates with a natural fundamental frequency of 220 Hz, with a wavelength of 2m.
Besides 220 Hz, which of the following are "resonant frequencies" which you might also faintly
detect?
i) 110 Hz
ii) 330 Hz
iii) 440 Hz
A: i only
D: i and ii
B: ii only
E: I, ii and iii
C: iii only
28. Two travelling waves 1 and 2 are described by the equations.
y1(x,t) = 2 sin(3x + t)
y2(x,t) = 4 sin( x – 6t)
All the numbers are in the appropriate SI (mks) units. The wavelength  of wave 1 is most nearly
A: 1m
B: 2m
C: 3m
D: 4m
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Spring 2013 - PHYS 2130 review for final exam – Answers will appear on Friday 04/26/13 on
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29. Two pulses on a string approach each other at speeds of 1 m/s. What is the shape of the string
at t=6 s?
30. A string has two asymmetrical pulses approaching each other traveling at 1 m/s.
1m
What will the string look like 5 seconds later?
1m
A
1m
B
1m
C
1m
D
1m
E
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Spring 2013 - PHYS 2130 review for final exam – Answers will appear on Friday 04/26/13 on
last page
Answers will be posted here in a day or two (definitely by Friday 04/26/13 5pm)
Answers
1 –D
2 –C
3 –B
4 –C
5 –C
6 –A
7 –D
8 –B
9 –B
10 –E
11 –A
12 –E
13 –D
14 –B
15 –A
16 –C
17 –A
18 –B
19 –A
20 –B
21 –B
22 –D
23 –D
24 –D
25 –D
26 –A
27 –C
28 –B
29 –C
30 –D
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