Multiple
Choice
Identify the letter of the choice that best completes the statement or answers the
question.
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1.
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A student walks to class at a
velocity of 3 m/s. To avoid walking into a door as it opens, the student slows to a velocity of 0.5
m/s. Now late for class, the student runs down the corridor at a velocity of 7 m/s. The student had
the least momentum a. | while walking at a velocity of 3
m/s. | b. | while dodging the opening door. | c. | immediately after the door opened. | d. | while running to class at a velocity of 7 m/s. | | |
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2.
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The change in an object’s
momentum is equal to a. | the product of the mass of the object and
the time interval. | b. | the product of the force applied to the
object and the time interval. | c. | the time interval divided by the net
external force. | d. | the net external force divided by the time
interval. | | |
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3.
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A ball with a momentum of 4.0
kg·m/s hits a wall and bounces straight back
without losing any kinetic energy. What is the change in the ball’s
momentum? a. | 0.0 kg·m/s | c. | 8.0 kg·m/s | b. | –4.0 kg·m/s | d. | –8.0 kg·m/s | | | | |
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4.
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A ball with a mass of 0.15 kg
and a velocity of 5.0 m/s strikes a wall and bounces straight back with a velocity of 3.0 m/s. What
is the change in momentum of the ball? a. | –0.30 kg·m/s | c. | –0.15 kg·m/s | b. | –1.20 kg·m/s | d. | –7.50 kg·m/s | | | | |
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5.
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After colliding, objects are
deformed and lose some kinetic energy. Identify the type of collision. a. | elastic | c. | inelastic | b. | perfectly
elastic | d. | perfectly inelastic | | | | |
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6.
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Which of the following best
describes the kinetic energy of each object after a two-body collision if the momentum of the system
is conserved? a. | must be less | c. | might also be
conserved | b. | must also be conserved | d. | is doubled in
value | | | | |
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7.
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A flashlight bulb with a
potential difference of 4.5 V across it has a resistance of 8.0 W. How much current is in the bulb filament? a. | 3.7 A | c. | 9.4 A | b. | 1.8 A | d. | 0.56 A | | | | |
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8.
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An electric toaster requires
1100 W at 110 V. What is the resistance of the heating coil? a. | 7.5 W | c. | 1.0 ´
101 W | b. | 9.0 W | d. | 11 W | | | | |
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9.
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Which compass needle
orientation in the figure above might correctly describe the magnet’s field at that
point?
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10.
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The current in a long wire
creates a magnetic field in the region around the wire. How is the strength of that field at a given
distance, r, from the wire’s center related to r? a. | the field is directly proportional to r | c. | the field is directly proportional to
r2 | b. | the field is inversely proportional to
r | d. | the field is inversely proportional to
r2 | | | | |
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Short
Answer
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11.
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What property was discovered in
Millikan’s experiments? Explain this property.
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12.
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Electrons move from the south
to the north in a wire. What is the direction of the magnetic field at a point directly above the
wire?
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Problem
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13.
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What is the electric force
between a proton and an alpha particle (charge 2e) that are separated by a distance of 3.0
´ 10–6 m? (e = 1.60
´ 10–19 C,
kc = 8.99 ´
109 N·m2/C2)
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14.
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What is the electric force
between an electron and a potassium nucleus (charge 19e) that are separated by a distance of
5.2 ´ 10–10 m? (e = 1.60
´ 10–19 C,
kc = 8.99 ´
109 N·m2/C2)
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