Multiple Choice Identify the
choice that best completes the statement or answers the question.
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1.
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Which has greater linear speed, a horse near the outside rail of a
merry-go-round or a horse near the inside rail?
a. | The inside horse | b. | The outside horse | c. | Neither—they
both have the same linear speed. |
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2.
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Which has greater angular speed, a horse near the outside rail of a
merry-go-round or a horse near the inside rail?
a. | Neither—they both have the same angular speed. | b. | The inside
horse | c. | The outside horse |
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3.
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Which of the following is NOT a unit of rotational speed?
a. | Meters per second | b. | Revolutions per minute | c. | Revolutions per
second | d. | Rotations per second | e. | Rotations per
minute |
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4.
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What is the direction of the force that acts on clothes in the spin cycle of a
washing machine?
a. | Inward | b. | Down | c. | Outward | d. | Up |
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5.
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A tin can whirled on the end of a string moves in a circle because
a. | the can continually pulls on the string. | b. | once the can starts
moving, that is its natural tendency. | c. | there is a force on the can pulling it
outward. | d. | there is an inward force acting on the can. | e. | all of the
above |
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6.
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If you whirl a tin can on the end of a string and the string suddenly breaks,
the can will
a. | fly directly away from you. | b. | fly off, tangent to its circular
path. | c. | fly directly toward you. | d. | spiral in toward your hand. | e. | spiral away from
your hand. |
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7.
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A ladybug rests on the bottom of a tin can that is being whirled horizontally on
the end of a string. Since the ladybug, like the can, moves in a circle, there must be a force on it.
What exerts this force?
a. | Gravity | b. | The string | c. | There is no force
acting on it. | d. | The can | e. | Your hand |
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8.
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"Centrifugal forces" are an apparent reality to observers in a
reference frame that is
a. | rotating. | b. | an inertial reference
frame. | c. | moving at constant velocity. | d. | at rest. | e. | none of the
above |
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9.
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A person weighs less at the equator than at the poles. The reason for this has
to do with the
a. | tidal bulges. | b. | influence of the sun, moon, and all the
planets. | c. | higher temperature at the equator, and expansion of matter. | d. | spin of the
Earth. | e. | none of the above |
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10.
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As the rotational speed of a space habitat increases, the weight of people
inside
a. | decreases. | b. | increases. | c. | stays the
same. |
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11.
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A car travels in a circle with constant speed. The net force on the car
a. | is zero because the car is not accelerating. | b. | is directed forward,
in the direction of travel. | c. | is directed toward the center of the
curve. | d. | none of the above |
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12.
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If Earth rotated more slowly about its axis, your weight would
a. | decrease. | b. | increase. | c. | stay the
same. |
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13.
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To weigh less in the Northern Hemisphere, you should go
a. | west. | b. | east. | c. | south. | d. | north. |
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14.
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When a railroad train rounds a banked track, the centripetal force needed comes
not from friction, but from the
a. | vertical component of the normal force. | b. | horizontal component
of the normal force. | c. | normal force. | d. | none of the
above |
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15.
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The centripetal force exerted on stunt motorcyclist Biker Bob while riding on
the inner vertical surface of a circular track is
a. | friction. | b. | his weight. | c. | the normal
force. | d. | none of the above |
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16.
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Nellie Newton swings a rock into a circular path while holding an attached
string overhead. The string makes a 45-degree angle to the vertical (comprising a "conical
pendulum"). The centripetal force that holds the rock in its circular path is the
a. | vertical component of the string tension. | b. | horizontal component
of the string tension. | c. | tension in the string. | d. | none of the
above |
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17.
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Stunt motorcyclist Biker Bob rides his bike inside a futuristic rotating space
station-a giant rotating donut-shaped structure in space. The normal support force feels like weight
to him. As he rides his bike in the same direction that the station rotates, the normal force
a. | remains unaffected. | b. | increases. | c. | decreases. |
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18.
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Stunt motorcyclist Biker Bob rides his bike inside a futuristic rotating space
station—a giant rotating donut-shaped structure in space. The normal support force feels like
weight to him. As he rides his bike in the opposite direction to the station’s rotation, the
normal force
a. | remains unaffected. | b. | increases. | c. | decreases. |
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19.
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Suzie Spacewalker hovers in space beside a rotating space station in outer
space. Both she and the center of mass of the space station are at relative rest. If the space
station is in Earth orbit, then Suzie
a. | is also in Earth orbit. | b. | is not in Earth orbit. | c. | may or may not be in
Earth orbit. |
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20.
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A space habitat is designed so that the variation in g between a
person's head and feet is less than 0.01 g. If the person is 2 m tall, then the radius of
the habitat is
a. | 20 m. | b. | 200 m. | c. | 2000
m. | d. | more than 2000 m. |
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Problem
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21.
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You sit at the outer rim of a Ferris wheel that rotates at 2 revolutions per
minute (RPM). What would your rotational speed be if you were instead clinging to a position halfway
from the center to the outer rim?
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22.
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A vertical pole standing against a wall topples to the ground and the center of
the pole has a speed of 13 m/s as it hits. With what speed does the far end of the pole hit the
ground?
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23.
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Tapered rims on railroad-train wheels enable a train to round curves without any
wheel skidding. Consider a curve where the outer track is one part in 50 longer than the inner track.
The wide part of the rim should have a diameter wider than the narrow part by at least one part
in
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24.
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At the outer edge of a rotating space habitat, 130 m from its center, the
rotational acceleration is g. What is the rotational acceleration at a distance of 65 m from
the center of the habitat?
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25.
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The tangential speed at the outer rim of a Ferris wheel is 10 m/s. What is the
tangential speed of a position half way from the center to the outer rim?
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