Download Physics Midterm Review Multiple Choice Identify the choice that best

Physics Midterm Review
Multiple Choice
Identify the choice that best completes the statement or answers the question.
____
1. Which of the following situations represents a negative displacement? (Assume positive position is measured vertically
upward along a y-axis.)
a. A cat stands on a tree limb.
b. A cat jumps from the ground onto a tree limb.
c. A cat jumps from a lower tree limb to a higher one.
d. A cat jumps from a tree limb to the ground.
____
2. According to the graph above, during which interval is the cat at rest?
a. 0.0–5.0 s
c. 10.0–15.0 s
b. 5.0–10.0 s
d. 15.0–20.0 s
____
3. According to the graph above, the cat has the fastest speed during which interval?
a. 0.0–5.0 s
c. 10.0–15.0 s
b. 5.0–10.0 s
d. 15.0–20.0 s
____
4. According to the graph above, during which interval does the cat have the greatest positive velocity?
a. 0.0–5.0 s
c. 10.0–15.0 s
b. 5.0–10.0 s
d. 15.0–20.0 s
____
5. When a car’s velocity is positive and its acceleration is negative, what is happening to the car’s motion?
a. The car slows down.
c. The car travels at constant speed.
b. The car speeds up.
d. The car remains at rest.
____
6. When a car’s velocity is negative and its acceleration is negative, what is happening to the car’s motion?
a. The car slows down.
c. The car travels at constant speed.
b. The car speeds up.
d. The car remains at rest.
____
7. When there is no air resistance, objects of different masses dropped from rest
a. fall with equal accelerations and with equal displacements.
b. fall with different accelerations and with different displacements.
c. fall with equal accelerations and with different displacements.
d. fall with different accelerations and with equal displacements.
____
8. Which would fall with greater acceleration in a vacuum—a leaf or a stone?
a. the leaf
b. the stone
c. They would accelerate at the same rate.
d. It is difficult to determine without more information.
____
9. Which of the following statements does not describe force?
a. Force causes objects at rest to remain stationary.
b. Force causes objects to start moving.
c. Force causes objects to stop moving.
d. Force causes objects to change direction.
____
10. A free-body diagram represents all of the following except
a. the object.
c. forces exerted by the object.
b. forces as vectors.
d. forces exerted on the object.
____
11. The free-body diagram shown above represents a car being pulled by a towing cable. In the diagram, which of the
following is the gravitational force acting on the car?
a. 5800 N
c. 14 700 N
b. 775 N
d. 13 690 N
____
12. Which of the following is the tendency of an object to maintain its state of motion?
a. acceleration
c. force
b. inertia
d. velocity
____
13. A car goes forward along a level road at constant velocity. The additional force needed to bring the car into equilibrium
is
a. greater than the normal force times the coefficient of static friction.
b. equal to the normal force times the coefficient of static friction.
c. the normal force times the coefficient of kinetic friction.
d. zero.
____
14. As an object falls toward Earth,
a. the object does not exert a force on Earth.
b. the object exerts a downward force on Earth.
c. Newton’s third law does not apply.
d. the upward acceleration of Earth is negligible because of its large mass.
____
15. A hockey stick hits a puck on the ice. Identify an action-reaction pair in this situation.
a. The stick exerts a force on the puck; the puck exerts a force on the stick.
b. The stick exerts a force on the puck; the puck exerts a force on the ice.
c. The puck exerts a force on the stick; the stick exerts a force on the ice.
d. The stick exerts a force on the ice; the ice exerts a force on the puck.
____
16. The magnitude of the gravitational force acting on an object is
a. frictional force.
c. inertia.
b. weight.
d. mass.
____
17. A force does work on an object if a component of the force
a. is perpendicular to the displacement of the object.
b. is parallel to the displacement of the object.
c. perpendicular to the displacement of the object moves the object along a path that returns the object
to its starting position.
d. parallel to the displacement of the object moves the object along a path that returns the object to its
starting position.
____
18. In which of the following scenarios is work done?
a. A weightlifter holds a barbell overhead for 2.5 s.
b. A construction worker carries a heavy beam while walking at constant speed along a flat surface.
c. A car decelerates while traveling on a flat stretch of road.
d. A student holds a spring in a compressed position.
____
19. A construction worker pushes a wheelbarrow 5.0 m with a horizontal force of 50.0 N. How much work is done by the
worker on the wheelbarrow?
a. 10 J
c. 250 J
b. 55 J
d. 1250 J
____
20. Which of the following energy forms is associated with an object in motion?
a. potential energy
c. nonmechanical energy
b. elastic potential energy
d. kinetic energy
____
21. Which of the following energy forms is associated with an object due to its position?
a. potential energy
c. total energy
b. positional energy
d. kinetic energy
____
22. What is the potential energy of a 1.0 kg mass 1.0 m above the ground?
a. 1.0 J
c. 10 J
b. 9.8 J
d. 96 J
____
23. Which of the following is a true statement about the conservation of energy?
a. Potential energy is always conserved.
b. Kinetic energy is always conserved.
c. Mechanical energy is always conserved.
d. Total energy is always conserved.
____
24. Which of the following is the rate at which energy is transferred?
a. potential energy
c. mechanical energy
b. kinetic energy
d. power
____
25. What is the term for the net force directed toward the center of an object’s circular path?
a. circular force
c. centripetal force
b. centrifugal force
d. orbital force
____
26. Which of the following can be a centripetal force?
a. friction
c. tension
b. gravity
d. all of the above
27. A child rides a bicycle in a circular path with a radius of 2.0 m. The tangential speed of the bicycle is 2.0 m/s. The
combined mass of the bicycle and the child is 43 kg. What kind of force provides the centripetal force on the bicycle?
a. gravitational force
c. air resistance
b. friction
d. normal force
____
____
28. Why does an astronaut weigh less on the moon than on Earth?
a. The astronaut has less mass on the moon.
b. The astronaut is farther from Earth’s center when he or she is on the moon.
c. The gravitational field strength is less on the moon’s surface than on Earth’s surface.
d. The astronaut is continually in free fall because the moon orbits Earth.
____
29. Which of the following is an example of a vector quantity?
a. velocity
c. volume
b. temperature
d. mass
____
30. In the figure above, which diagram represents the vector addition C = A + B?
a. I
c. III
b. II
d. IV
31. Which of the following is an example of projectile motion?
a. a jet lifting off a runway
b. a thrown baseball
c. an aluminum can dropped straight down into the recycling bin
d. a space shuttle being launched
____
____
32. Which of the following is not an example of projectile motion?
a. a volleyball served over a net
c. a hot-air balloon drifting toward Earth
b. a baseball hit by a bat
d. a long jumper in action
Short Answer
33. A motorized scooter starts from rest and accelerates for 4 s at 2 m/s . It continues at a constant speed for 6 s.
Graph the scooter’s velocity versus time. Explain how you could use the graph to show that the scooter’s
acceleration is constant during the intervals 1.0–2.0 s and 5.0–6.0 s.
34. What is the term for the curved, parabolic path that an object follows when thrown, launched, or otherwise
projected near the surface of the Earth?
The figure above shows the path of a ball tossed from a building. Air resistance is ignored.
35. In the figure above, what would happen to the height of the ball’s path if it were launched with a greater
velocity?
36. In the figure above, what would happen to the width of the ball’s path if it were launched with a greater
velocity?
37. Describe the graph of the horizontal component of velocity versus time for the motion of the ball shown in the
figure above.
38. Describe the graph of the vertical component of velocity versus time for the motion of the ball shown in the
figure above. Identify any constants that would appear in the graph.
39. Why is force not a scalar quantity?
40. A block of wood supported by two concrete blocks is chopped in half by a karate instructor. Identify an
action-reaction pair, and compare the forces exerted by each object.
41. In what direction does the force of air resistance act?
42. Two horses are side by side on a carousel. Which has a greater tangential speed—the one closer to the center
or the one farther from the center? Explain your answer.
43. Distinguish between the displacement of a traveler who takes a train from New York to Boston and the
displacement of a traveler who flies from Boston to New York.
44. Explain how a dog that has moved can have a displacement of zero.
45. What is free fall?
46. How are the velocity and speed of a vertically thrown baseball moving upward in free fall changing? (Assume
a = g = 9.81 m/s .)
47. The length of a vector arrow in a diagram is proportional to what property of the vector?
48. What is a projection of a vector along an axis of a coordinate system called?
49. If the magnitude of a vector component equals the magnitude of the vector, then what is the magnitude of the
other vector component?
50. Briefly describe how applying the brakes to stop a bicycle is an example of force.
51. What happens to an object in motion when it experiences a nonzero net external force?
52. Describe the forces acting on a car as it moves along a level highway in still air at a constant speed.
53. Why does it require much less force to accelerate a low-mass object than it does to accelerate a high-mass
object the same amount?
54. How do mass and weight vary with altitude?
55. Distinguish between mass and weight.
56. When a car is moving, what happens to the velocity and acceleration of the car if the air resistance becomes
equal to the force acting in the opposite direction?
57. Explain how an object moving at a constant speed can have a nonzero acceleration.
58. What provides the centripetal force for a ball whirled on a string?
59. Is there an outward force in circular motion? Explain.
60. What provides the centripetal force for the moon’s orbit around Earth?
Problem
61. A shopping cart is given an initial velocity of 2.0 m/s and undergoes a constant acceleration of 2.0 m/s . What
is the magnitude of the cart’s displacement after the first 6.0 s of its motion?
62. A skater glides off a frozen pond onto a patch of ground at a speed of 2.9 m/s. Here she is slowed at a
constant rate of 3.00 m/s . How fast is the skater moving when she has slid 0.38 m across the ground?
63. Human reaction time is usually about 0.20 s. If your lab partner holds a ruler between your finger and thumb
and releases it from rest without warning, how far can you expect the ruler to fall before you catch it?
(Disregard air resistance. a = g = 9.81 m/s .)
64. A stagehand starts sliding a large piece of stage scenery originally at rest by pulling it horizontally with a
force of 177 N. What is the coefficient of static friction between the stage floor and the 230 N piece of
scenery?
65. What centripetal force is exerted on the roller car at the lowest point?
66. A hiker travels south along a straight path for 1.2 h with an average speed of 4.1 km/h and then travels north
for 1.7 h with an average speed of 4.7 km/h. What is the hiker’s displacement for the total trip?
67. A rock is thrown straight upward with an initial velocity of 6.4 m/s in a location where the acceleration due to
gravity has a magnitude of 9.81 m/s . To what height does it rise?
68. A cave explorer travels 2.0 m eastward, then 2.4 m northward, and finally 18.0 m westward. Use the graphical
method to find the magnitude of the net displacement.
69. An athlete runs 130 m across a level field at an angle of 22.0 north of east. What is the north component of
this displacement?
70. What is the magnitude of the resultant displacement of a dog looking for its bone in the yard if the dog first
heads 57.0 north of west for 10.3 m and then turns and heads west for 4.00 m?
71. A stone is thrown at an angle of 30.0 above the horizontal from the top edge of a cliff with an initial speed of
15 m/s. A stopwatch measures the stone’s trajectory time from the top of the cliff to the bottom at 6.30 s.
What is the height of the cliff? (Assume no air resistance and that a = g = 9.81 m/s .)
72. A model rocket flies horizontally off the edge of a cliff at a velocity of 70.0 m/s. If the canyon below is 110.0
m deep, how far from the edge of the cliff does the model rocket land? (a = g = 9.81 m/s )
73. A farmhand attaches a 27 kg bale of hay to one end of a rope passing over a frictionless pulley connected to a
beam in the hay barn. Another farmhand then pulls down on the opposite end of the rope with a force of 397
N. Ignoring the mass of the rope, what will be the magnitude and direction of the bale’s acceleration if the
gravitational force acting on it is 265 N?
74. Basking in the sun, a 1.97 kg lizard lies on a flat rock tilted at an angle of 15.9 with respect to the horizontal.
What is the magnitude of the normal force exerted by the rock on the lizard?
75. A rope attached to an engine pulls a 240 N crate up an 14.7° ramp at constant speed. The coefficient of kinetic
friction for the surfaces of the crate and ramp is 0.32. What is the magnitude of the force that the rope exerts
on the crate parallel to the ramp? (g = 9.81 m/s )
76. A couch with a mass of 1.00  10 kg is placed on an adjustable ramp connected to a truck. As one end of the
ramp is raised, the couch begins to move downward. If the couch slides down the ramp with an acceleration
of 0.79 m/s when the ramp angle is 12.0, what is the coefficient of kinetic friction between the ramp and the
couch? (g = 9.81 m/s )
77. A car on a roller coaster loaded with passengers has a mass of 2.0  10 kg. At the lowest point of the track,
the radius of curvature of the track is 24 m and the roller car has a tangential speed of 17 m/s. What is the
centripetal acceleration of the roller car at the lowest point on the track?
78. A 69.8 kg student sits at a desk 1.75 m away from a 78.9 kg student. What is the magnitude of the
gravitational force between the two students? (G = 6.673  10 Nm /kg )
79. Two trucks with equal mass are attracted to each other with a gravitational force of 5.3  10 N. The trucks
are separated by a distance of 2.6 m. What is the mass of either of the trucks? (G = 6.673  10 Nm /kg )
Physics Midterm Review
Answer Section
MULTIPLE CHOICE
1. ANS: D
.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
PTS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
1
B
C
A
A
B
A
C
A
C
C
B
D
D
A
B
B
C
C
DIF:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
I
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
OBJ:
DIF:
DIF:
DIF:
DIF:
DIF:
DIF:
DIF:
DIF:
DIF:
DIF:
DIF:
DIF:
DIF:
DIF:
DIF:
DIF:
DIF:
2-1.1
II
II
II
II
II
I
I
I
I
II
I
I
II
II
I
I
I
OBJ:
OBJ:
OBJ:
OBJ:
OBJ:
OBJ:
OBJ:
OBJ:
OBJ:
OBJ:
OBJ:
OBJ:
OBJ:
OBJ:
OBJ:
OBJ:
OBJ:
2-1.3
2-1.3
2-1.3
2-2.1
2-2.1
2-3.3
2-3.3
4-1.1
4-1.2
4-1.2
4-2.1
4-2.3
4-3.3
4-3.3
4-4.1
5-1.2
5-1.3
Given
Solution
PTS: 1
20. ANS: D
21. ANS: A
22. ANS: B
Given
DIF: IIIA
PTS: 1
PTS: 1
OBJ: 5-1.4
DIF: I
DIF: I
OBJ: 5-2.1
OBJ: 5-2.1
Solution
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
PTS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
1
D
D
C
D
B
C
A
B
B
C
DIF:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
IIIA
1
1
1
1
1
1
1
1
1
1
OBJ:
DIF:
DIF:
DIF:
DIF:
DIF:
DIF:
DIF:
DIF:
DIF:
DIF:
5-2.6
I
I
I
I
II
II
I
I
I
I
OBJ:
OBJ:
OBJ:
OBJ:
OBJ:
OBJ:
OBJ:
OBJ:
OBJ:
OBJ:
5-3.1
5-4.1
7-1.2
7-1.2
7-1.2
7-2.1
3-1.1
3-1.2
3-3.1
3-3.1
SHORT ANSWER
33. ANS:
The scooter’s acceleration is constant during both intervals because the velocity versus time graph is a straight
line for each of the intervals.
PTS: 1
34. ANS:
projectile motion
DIF: I
OBJ: 2-2.2
PTS: 1
35. ANS:
DIF: I
OBJ: 3-3.1
The height of the ball’s path would increase.
PTS: 1
DIF: I
OBJ: 3-3.2
36. ANS:
The width of the ball’s path would increase.
PTS: 1
DIF: I
OBJ: 3-3.2
37. ANS:
The graph of the horizontal component of the velocity versus time is a straight line parallel to the time axis.
PTS: 1
DIF: I
OBJ: 3-3.2
38. ANS:
The graph of the vertical component of the velocity versus time is a straight line with a negative slope. The
slope of the line is 9.81 m/s , which is g
PTS: 1
DIF: II
OBJ: 3-3.2
39. ANS:
A scalar quantity has only magnitude. Force has both magnitude and direction, so it cannot be a scalar
quantity.
PTS: 1
DIF: II
OBJ: 4-1.2
40. ANS:
The hand exerts a force on the wood, and the wood exerts an equal force on the hand. Each end of the wood
exerts a force on a block, and each block exerts an equal force on the wood.
PTS: 1
DIF: II
OBJ: 4-3.3
41. ANS:
Air resistance acts in the direction opposite the direction of an object’s motion.
PTS: 1
DIF: I
OBJ: 4-4.3
42. ANS:
The horse farther from the center has a greater tangential speed. Although both horses complete one circle in
the same time period, the one farther from the center covers a greater distance during that time period.
PTS: 1
DIF: II
OBJ: 7-1.1
43. ANS:
The magnitudes of the displacements are equal, but the displacements are in opposite directions. Therefore,
one displacement is positive and one displacement is negative.
PTS: 1
DIF: II
OBJ: 2-1.1
44. ANS:
The dog’s initial position and its final position are the same position.
PTS: 1
DIF: II
OBJ: 2-1.1
45. ANS:
Free fall is the motion of an object falling with a constant acceleration due to gravity in the absence of air
resistance.
PTS: 1
DIF: I
OBJ: 2-3.1
46. ANS:
Both the baseball’s velocity and speed are decreasing.
PTS: 1
DIF: II
OBJ: 2-3.2
47. ANS:
The length of the vector arrow is proportional to the magnitude of the vector.
PTS: 1
DIF: I
48. ANS:
a component of the vector
OBJ: 3-1.1
PTS: 1
49. ANS:
zero
OBJ: 3-2.3
DIF: I
PTS: 1
DIF: II
OBJ: 3-2.3
50. ANS:
Force causes an acceleration, or a change in an object’s velocity. Applying the brakes decelerates the bicycle
(accelerates it in the negative direction) and causes a change in the bicycle’s velocity because the bicycle
slows down.
PTS: 1
DIF: II
51. ANS:
The object experiences an acceleration.
OBJ: 4-1.1
PTS: 1
DIF: I
OBJ: 4-2.1
52. ANS:
Gravity exerts a downward force on the car that is balanced by the normal force of the road acting upward on
the car. The car’s forward motion is opposed by the friction between the road and the tires and by the
resistance of the air. The sum of these opposing forces is balanced by an equal and opposite force exerted by
the engine and applied to the tires, where the road exerts a reaction force that is directed forward.
PTS: 1
DIF: II
OBJ: 4-2.2
53. ANS:
An object with smaller mass has less inertia, or tendency to maintain velocity, than does an object with
greater mass.
PTS: 1
DIF: II
OBJ: 4-3.1
54. ANS:
Mass remains constant, but weight decreases with altitude.
PTS: 1
DIF: I
OBJ: 4-4.1
55. ANS:
Mass is the amount of matter in an object and is an inherent property of an object. Weight is not an inherent
property of an object and is the magnitude of the force due to gravity acting on the object.
PTS: 1
DIF: II
OBJ: 4-4.1
56. ANS:
The acceleration is then zero, and the car moves at a constant velocity.
PTS: 1
DIF: I
OBJ: 4-4.3
57. ANS:
Acceleration depends on the change in an object’s velocity. An object moving at a constant speed can
experience a nonzero acceleration if the direction of the object’s motion changes.
PTS: 1
DIF: II
OBJ: 7-1.1
58. ANS:
Tension in the string provides the centripetal force.
PTS: 1
DIF: II
OBJ: 7-1.2
59. ANS:
No, there is only an inward force causing a deviation from a straight-line path. The tendency to move in a
straight line away from the circular path is inertia.
PTS: 1
DIF: II
OBJ: 7-1.3
60. ANS:
The gravitational force between Earth and the moon provides the centripetal force.
PTS: 1
DIF: II
OBJ: 7-2.1
DIF: IIIA
OBJ: 2-2.3
PROBLEM
61. ANS:
48 m
Given
v = 2.0 m/s
a = 2.0 m/s
t = 6.0 s
Solution
PTS: 1
62. ANS:
2.5 m/s
Given
v = 2.9 m/s
a = 3.00 m/s
x = 0.38 m
Solution
PTS: 1
63. ANS:
at least 0.20 m
DIF: IIIA
OBJ: 2-2.3
DIF: IIIA
OBJ: 2-3.2
DIF: IIIB
OBJ: 4-4.4
Given
a = g =9.81 m/s
t = 0.20 s
v = 0.0 m/s
Solution
PTS: 1
64. ANS:
0.77
Given
F
F
177 N
230 N
Solution
PTS: 1
65. ANS:
2.4  10 N
Given
Solution
PTS: 1
66. ANS:
3.1 km, north
DIF: IIIA
OBJ: 7-1.2
Given
v
= 4.1 km/h
t = 1.2 h
v
= 4.7 km/h
t = 1.7 h
Solution
x = x + x = v
t + v
t
x = (4.1 km/h)(1.2 h) + (4.7 km/h)(1.7 h)
x = –4.9 km/h + 8.0 km/h = +3.1 km = 3.1 km, north
PTS: 1
67. ANS:
2.1 m
DIF: IIIB
OBJ: 2-1.2
DIF: IIIB
OBJ: 2-3.2
Given
a = g = 9.81 m/s
v = 6.4 m/s
v = 0.0 m/s
Solution
PTS: 1
68. ANS:
16.2 m
Solution
Students should use graphical techniques. Their answers can be checked using the techniques presented in
Section 2.
PTS: 1
69. ANS:
49 m
DIF: IIIA
Given
d 130 m
OBJ: 3-1.2
22.0
Solution
PTS: 1
70. ANS:
12.92 m
DIF: IIIA
Given
d
10.3 m at 57.0 north of west
d
4.00 m west
d
d
10.3 m
4.00 m
Solution


57.0
0.0
OBJ: 3-2.3
PTS: 1
71. ANS:
148 m
DIF: IIIB
OBJ: 3-2.4
Given
v 15 m/s at 30.0° above the horizontal
t 6.30 s
g 9.81 m/s
Solution
PTS: 1
72. ANS:
DIF: IIIB
Given
v 70.0 m/s horizontally
OBJ: 3-3.3
y
110.0 m
Solution
PTS: 1
73. ANS:
4.9 m/s , upward
Given
F
F
m
DIF: IIIB
OBJ: 3-3.3
DIF: IIIA
OBJ: 4-3.2
397 N
265 N
27 kg
Solution
a
4.9 m/s , upward
PTS: 1
74. ANS:
18.6 N
Given
m = 1.97 kg
= 15.9
g = 9.81 m/s
Solution
PTS: 1
75. ANS:
135 N
DIF: IIIA
OBJ: 4-4.2
DIF: IIIB
OBJ: 4-4.4
Given
F
240 N
 14.7
 0.32
Solution
PTS: 1
76. ANS:
0.131
Given
m 1.00  10 kg
a
0.79 m/s
 12.0
g 9.81 m/s
Solution
PTS: 1
77. ANS:
12 m/s
DIF: IIIC
OBJ: 4-4.4
DIF: IIIA
OBJ: 7-1.1
Given
Solution
PTS: 1
78. ANS:
Given
Solution
PTS: 1
79. ANS:
7.3  10 kg
DIF: IIIA
OBJ: 7-2.2
DIF: IIIC
OBJ: 7-2.2
Given
Solution
PTS: 1