Transcript Conceptual Questions Chapter 7

A rigid object is rotating with an angular speed
w > 0. The angular velocity vector w and the
angular acceleration vector a are anti-parallel.
The angular speed of the rigid object is
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2
3
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1. clockwise and
increasing.
2. clockwise and
decreasing.
3. counterclockwise and
increasing.
4. counterclockwise and
decreasing.
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4
The Earth remains in orbit about the Sun,
rather than falling in to the Sun, because
1.
2.
3.
4.
it is outside of the
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gravitational influence of the
Sun.
the net force on the Earth is
zero.
although the Earth is
constantly being pulled
toward the Sun, it is always
moving with a velocity
component perpendicular to
the direction that it is being
pulled.
none of these apply.
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25%
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3
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A planet has 3 moons, all of equal mass. Moon 1 is in a
circular orbit of radius r. Moon 2 is in a circular orbit of radius
2r, and moon 3 is in a circular orbit of radius 3r. The ratios of
the gravitational force exerted by the planet on each of the
moons, 1, 2, and 3 are ________ respectively.
25%
1.
2.
3.
4.
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2
3
25%
1:2:3
1:1:1
1:4:9
9:4:1
1
4
A space station orbits the Earth with constant
speed. What can be said about the space station's
acceleration?
1. It is zero because the space
station moves with constant
speed.
2. It is greater than 9.8 m/s2
because the space station is
moving so quickly.
3. It is less than 9.8 m/s2
because the space station is
so high above the Earth’s
surface.
4. It is equal to 9.8 m/s2.
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3
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4
Mercury, the closest planet to the Sun,
has an orbital period that is
1. greater than that of all
of the other planets.
2. less than that of all of
the other planets.
3. greater than that of
some of the planets
and less than that of
others.
4. equal to one Earth
year.
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3
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4
Consider an asteroid that orbits the Sun
once every 5 years. Does this object ever
cross the Earth's orbital path?
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2
3
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1. Yes, it must cross
twice every five earth
years.
2. No, it can never cross
Earth’s orbital path.
3. Yes, it must cross
once every Earth
year.
4. It is impossible to tell.
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4
Which of the following forms of energy is the
greatest for a system of a comet in orbit about the
Sun during perihelion (the comet's closest approach
to the Sun).
25%
25%
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1. the total mechanical
energy
2. the potential energy
3. the kinetic energy
4. none of these
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2
3
4
Which of the following trips would consume
more fuel for a given spacecraft?
1. a trip from the Earth to
the Moon
2. a trip from the moon
to the Earth
3. They both require the
same amount of fuel.
4. It is impossible to
determine.
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25%
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3
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On which planet would you experience the
highest gravitational acceleration?
1. on one with twice the
radius of the Earth and
twice the mass
2. on one with half the
radius of the Earth and
half the mass
3. on the Earth
4. on one with twice the
radius of the Earth and
half the mass
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25%
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2
3
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4
Select the best phrase to complete the
following statement: "The gravitational force
of the Earth
1. affects all objects
equally."
2. on an object is a function
of an object's mass."
3. has no effect on the rate
at which objects
accelerate as they fall."
4. is exactly the same size
for a given object
everywhere on the Earth."
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You can determine the mass of the Moon
1.
2.
3.
4.
by measuring how long it
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takes to revolve around
the Earth.
by measuring its distance
from the Earth.
by measuring its
diameter as well as the
rate at which objects
accelerate due to gravity
on the Moon.
by doing any of these.
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3
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4