Chapter
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7
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Chapter Summary
Image Bank
Chapter Assessment Questions
Transparencies
Standardized Test Practice
Video Clips
and Animations
Chapter
7
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Chapter
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Comet Hale-Bopp
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Planetary Data
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Sketch of Orbits of Lo and Callisto
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Universal Gravitation and Kepler’s Third Law
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Cavendish Balance
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Orbits of Planets and Satellites
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Landsat 7
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Sketching Satellite’s Orbit Around Earth
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Astronaut Chiaki Mukai Experiencing Weightlessness
Aboard Space Shuttle Columbia
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The Gravitational Field
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Vectors Representing Earth’s Gravitational Field
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Inertial Balance
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Rubber Sheet Illustrating Effect of Mass on Space
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Deflection of Light
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Chandra X-ray Image of Two Black Holes
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Standardized Test Practice (Q. 2)
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Standardized Test Practice (Q. 5)
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Transparencies
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Transparencies
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Video Clips and Animations
Kepler’s First Law
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Chapter
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Video Clips and Animations
Kepler’s Second Law
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Chapter
7
Video Clips and Animations
Kepler’s Third Law
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Chapter
7
Video Clips and Animations
Newton’s Law of Universal Gravitation
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Video Clips and Animations
Inverse Square Law
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Video Clips and Animations
Cavendish Experiment
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Video Clips and Animations
Orbits of Planets and Satellites
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Video Clips and Animations
Two Kinds of Mass
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Section
7.1
Chapter Summary
Planetary Motion and Gravitation
Kepler’s first law states that the paths of the planets are ellipses,
with Sun at one focus.
Kepler’s second law states that an imaginary line from the Sun
to a planet sweeps out equal areas in equal time intervals.
Kepler’s third law states that the square of the ratio of the
periods of any two planets revolving about the Sun is equal to
the cube of the ratio of their average distances from the Sun.
Section
7.1
Chapter Summary
Planetary Motion and Gravitation
Newton’s law of universal gravitation states that the gravitational
force between any two objects is directly proportional to the
product of their masses and inversely proportional to the square
of the distance between their centers. The force is attractive and
along a line connecting their centers.
Section
7.1
Chapter Summary
Planetary Motion and Gravitation
Newton’s law of universal gravitation can be used to rewrite
Kepler’s third law to relate the radius and period of a planet to
the mass of the Sun.
Section
7.2
Chapter Summary
Using the Law of Universal Gravitation
The speed of an object in circular orbit is given by the following
expression:
Section
7.2
Chapter Summary
Using the Law of Universal Gravitation
The period of a satellite in a circular orbit is given by the
following expression:
All objects have gravitational field surrounding them.
Section
7.2
Chapter Summary
Using the Law of Universal Gravitation
Gravitational mass and inertial mass are two essentially different
concepts. The gravitational and inertial masses of an object,
however, are numerically equal.
Section
7.2
Chapter Summary
Using the Law of Universal Gravitation
Einstein’s general theory of relativity describes gravitational
attraction as a property of space itself.
Chapter
7
Chapter Assessment Questions
Question 1
________ states that objects attract other objects with a force that is
proportional to the product of their masses and inversely
proportional to the square of the distance between them.
A. Kepler’s first law
B. Kepler’s second law
C. Kepler’s third law
D. Newton’s law of universal gravitation
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7
Chapter Assessment Questions
Answer 1
Answer: D
Reason: According to Newton’s law of universal gravitation:
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Chapter Assessment Questions
Question 2
A satellite orbiting Earth over the equator appears to remain over
one spot to an observer on Earth. What is its orbital speed?
A. Equal to Earth’s orbital speed around Sun
B. Equal to Earth’s rate of rotation
C. Zero
D. Data insufficient
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Chapter Assessment Questions
Answer 2
Answer: B
Reason: When the satellite’s orbital speed matches with Earth’s rate
of rotation, the satellite appears to remain over one spot on
the equator.
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Chapter Assessment Questions
Question 3
Describe a gravitational field.
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Chapter Assessment Questions
Answer 3
Any object with mass is surrounded by a gravitational field in which
another object experiences a force due to the interaction between its
mass and the gravitational field, g, at its location.
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7
Chapter Assessment Questions
Question 4
Differentiate between inertial mass and gravitational mass.
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Chapter Assessment Questions
Answer 4
Mass related to the inertia of an object is inertial mass. Inertial mass
is equal to the ratio of the net force exerted on an object to its
acceleration.
Mass as used in the law of universal gravitation determines the size
of the gravitational force between two objects and is called
gravitational mass.
Chapter
7
Chapter Assessment Questions
Question 5
If a lift carrying a person starts to fall freely toward Earth, the contact
force between the lift and the person inside the lift will be equal to:
A. Weight of the person
B. Weight of the lift
C. Zero
D. Gravitational force between the lift and Earth
Chapter
7
Chapter Assessment Questions
Answer 5
Answer: C
Reason: In a free fall toward Earth both, the lift and the person inside it
are falling toward Earth with the same acceleration. Hence,
the person experiences weightlessness.
Chapter
7
Standardized Test Practice
Multiple Choice
1.
Two satellites are in orbit around a planet. One satellite has an
orbital radius of 8.0×106 m. The period of rotation for this
satellite is 1.0×106 s. The other satellite has an orbital radius of
2.0×107 m. What is this satellite’s period of rotation?
A. 5.0×105 s
B. 2.5×106 s
C. 4.0×106 s
D. 1.3×107 s
Chapter
7
Standardized Test Practice
Multiple Choice
2.
The illustration on the right
shows a satellite in orbit
around a small planet. The
satellite’s orbital radius is
6.7×104 km and its speed is
2.0×105 m/s. What is the
mass of the planet around
which the satellite orbits? (G
= 6.7×10−11 N·m2/kg2)
A. 2.5×1018 kg
C. 4.0×1020 kg
B. 2.5×1023 kg
D. 4.0×1028 kg
Chapter
7
Standardized Test Practice
Multiple Choice
3.
Two satellites are in orbit around the same planet. Satellite A
has a mass of 1.5×102 kg, and satellite B has a mass of
4.5×103 kg. The mass of the planet is 6.6×1024 kg. Both
satellites have the same orbital radius of 6.8×106 m. What is the
difference in the orbital periods of the satellites?
A. No difference
B. 1.5×102 s
C. 2.2×102 s
D. 3.0×102 s
Chapter
7
Standardized Test Practice
Multiple Choice
4.
A moon revolves around a planet with a speed of 9.0×103 m/s.
The distance from the moon to the center of the planet is
5.4×106 m. What is the orbital period of the moon?
A. 1.2π×102 s
B. 6.0π×102 s
C. 1.2π×103 s
D. 1.2π×109 s
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Standardized Test Practice
Extended Answer
5.
A moon in orbit around a planet experiences a gravitational
force not only from the planet, but also from the Sun. The
illustration on the next slide shows a moon during a solar
eclipse, when the planet, the moon, and the Sun are aligned.
The moon has a mass of about 3.9×1021 kg. The mass of the
planet is 2.4×1026 kg, and the mass of the Sun is 2.0×1030 kg.
The distance from the moon to the center of the planet is
6.0×108 m, and the distance from the moon to the Sun is
1.5×1011 m. What is the ratio of the gravitational force on the
moon due to the planet, compared to its gravitational force due
to the Sun during the solar eclipse?
Chapter
Standardized Test Practice
7
Multiple Choice
A. 0.5
C. 5.0
B. 2.5
D. 7.5
Chapter
7
Standardized Test Practice
Extended Answer
6.
Two satellites are in orbit around a planet. Satellite S1 takes 20
days to orbit the planet at a distance of 2×105 km from the
center of the planet. Satellite S2 takes 160 days to orbit the
planet. What is the distance of satellite S2 from the center of the
planet?
Chapter
7
Standardized Test Practice
Test-Taking Tip
Plan Your Work and Work Your Plan
Plan your workload so that you do a little work each day, rather than
a lot of work all at once. The key to retaining information is repeated
review and practice. You will retain more if you study one hour a
night for five days in a row instead of cramming the night before a
test.
Chapter
7
Chapter Resources
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