Question 1

How does the speed of a communications satellite vary as it moves around Earth?

Accepted Answer

A) It is slowest at perigee. 
B) It is slowest at apogee. 
C) It must have the same speed all the way around. 
D) It slows continuously. 
A) It is slowest at perigee. 
B) It is slowest at apogee. 
C) It must have the same speed all the way around. 
D) It slows continuously.

Question 2

At what position in its orbit will an inferior planet appear to be moving, for a day or two, more or less directly toward Earth? (See Figure 4-6 of Universe, 11th ed., and draw a diagram if it will help.)
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Accepted Answer

A) greatest western elongation 
B) inferior conjunction 
C) superior conjunction 
D) greatest eastern elongation 
A) greatest western elongation 
B) inferior conjunction 
C) superior conjunction 
D) greatest eastern elongation

Question 3

As a spacecraft such as Voyager 2 moves away from the Sun, the gravitational force on it F varies with distance R from the Sun in which mathematical way? ( means "proportional to.")

Accepted Answer

A) F $\alpha$ 1/R 
B) F $\alpha$ R 
C) F = constant, independent of distance 
D) F $\alpha$ 1/R2 
A) F $\alpha$ 1/R 
B) F $\alpha$ R 
C) F = constant, independent of distance 
D) F $\alpha$ 1/R2

Question 4

Which of the following situations is not an acceptable orbital path for a body gravitationally bound to the Sun?

Accepted Answer

A) straight line ending at the Sun 
B) parabolic path beginning at the center of the galaxy 
C) along ellipse with the Sun at one focus 
D) circular path with the Sun on the circle 
A) straight line ending at the Sun 
B) parabolic path beginning at the center of the galaxy 
C) along ellipse with the Sun at one focus 
D) circular path with the Sun on the circle

Question 5

Two objects of different mass when dropped by an astronaut on the Moon have:

Accepted Answer

A) no acceleration at all in the airless space. 
B) the same acceleration. 
C) different accelerations proportional to their masses. 
D) different accelerations, the more massive object having the smaller acceleration. 
A) no acceleration at all in the airless space. 
B) the same acceleration. 
C) different accelerations proportional to their masses. 
D) different accelerations, the more massive object having the smaller acceleration.

Question 6

How many more orbits around the Sun in 1 synodic period of that planet does an inferior planet cover compared to Earth?

Accepted Answer

A) wrong way around-Earth does one more orbit compared to the planet 
B) two 
C) one 
D) a fraction of an orbit 
A) wrong way around-Earth does one more orbit compared to the planet 
B) two 
C) one 
D) a fraction of an orbit

Question 7

The sidereal period of Mars is 1.9 years. Use the appropriate formula in Box 4-1 to find the time from the middle of one retrograde loop for Mars to the middle of the next retrograde loop (assuming circular orbits for Mars and Earth). This time is:

Accepted Answer

A) 365 days. 
B) 694 days. 
C) 770 days. 
D) 1059 days. 
A) 365 days. 
B) 694 days. 
C) 770 days. 
D) 1059 days.

Question 8

Does the Sun or the Moon have a greater effect in causing the tides on Earth?

Accepted Answer

A) The Sun, because it exerts a stronger gravitational pull on Earth. 
B) The Moon, because it has a stronger gravitational pull on Earth. 
C) The Sun, because it has a larger difference between pulling on the near side and pulling on the far side of Earth. 
D) The Moon, because it has a larger difference between pulling on the near side and pulling on the far side of Earth. 
A) The Sun, because it exerts a stronger gravitational pull on Earth. 
B) The Moon, because it has a stronger gravitational pull on Earth. 
C) The Sun, because it has a larger difference between pulling on the near side and pulling on the far side of Earth. 
D) The Moon, because it has a larger difference between pulling on the near side and pulling on the far side of Earth.

Question 9

In the path of Mars against the background stars shown in Figure 4-2 of Universe, 11th ed., the planet appears from Earth to move in a loop, moving westward for a period of time. What is the approximate angle between the Earth-Sun line and the Earth-Mars line when the planet is halfway through the westward, or retrograde, motion on about June 1?
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Accepted Answer

A) 180° 
B) It can be any angle. 
C) 0° 
D) 90° 
A) 180° 
B) It can be any angle. 
C) 0° 
D) 90°

Question 10

An imaginary planet is orbiting the Sun in a circle at precisely the same average orbital distance as Earth (i.e., 1 au). What is its sidereal period?

Accepted Answer

A) about 8/10 of a year 
B) infinitely long 
C) 0 
D) 1 year 
A) about 8/10 of a year 
B) infinitely long 
C) 0 
D) 1 year

Question 11

Halley's Comet returns to the Sun's vicinity every 76 years in an elliptical orbit. What is the semimajor axis of this orbit?

Accepted Answer

A) 17.5 au 
B) 0.59 au 
C) 1 au 
D) 50.000 au 
A) 17.5 au 
B) 0.59 au 
C) 1 au 
D) 50.000 au

Question 12

Two spacecrafts that have different masses but rocket engines of identical force are at rest in space. If they fire their rockets at the same time, which ship will speed up fastest?

Accepted Answer

A) They will not speed up at all but will move at a constant speed since they are in space and the rocket has nothing against which to push. 
B) The one with the lower mass will speed up fastest. 
C) They will increase speed at the same rate since they have identical rocket engines. 
D) The one with the higher mass will speed up fastest. 
A) They will not speed up at all but will move at a constant speed since they are in space and the rocket has nothing against which to push. 
B) The one with the lower mass will speed up fastest. 
C) They will increase speed at the same rate since they have identical rocket engines. 
D) The one with the higher mass will speed up fastest.

Question 13

The gravitational pull of the Sun on the Moon is stronger than the gravitational pull of Earth on the Moon. Which of these is more important in raising tides on the Moon?

Accepted Answer

A) Because the Moon has no oceans it cannot experience tides. 
B) Because the Sun has the stronger pull it is clearly more important in raising tides. 
C) Earth is more important in raising tides on the Moon because the difference between the near-side and far-side forces caused by Earth is greater than the difference between the near-side and far-side forces caused by the Moon. 
D) The Moon is in a stable orbit because the gravitational effects of Earth and the Sun just balance. Thus, they are equally important in raising tides on the Moon. 
A) Because the Moon has no oceans it cannot experience tides. 
B) Because the Sun has the stronger pull it is clearly more important in raising tides. 
C) Earth is more important in raising tides on the Moon because the difference between the near-side and far-side forces caused by Earth is greater than the difference between the near-side and far-side forces caused by the Moon. 
D) The Moon is in a stable orbit because the gravitational effects of Earth and the Sun just balance. Thus, they are equally important in raising tides on the Moon.

Question 14

The Ptolemaic model of the universe included each of the following features, except one. Which one is the exception?

Accepted Answer

A) The Sun and the Moon revolve around Earth. 
B) The planets move in circular orbits called epicycles. The centers of the epicycles move along circular orbits called deferents. 
C) Comets are within Earth's atmosphere. 
D) The apparent daily motion of the stars is due to the rotation of Earth. 
A) The Sun and the Moon revolve around Earth. 
B) The planets move in circular orbits called epicycles. The centers of the epicycles move along circular orbits called deferents. 
C) Comets are within Earth's atmosphere. 
D) The apparent daily motion of the stars is due to the rotation of Earth.

Question 15

A small object is on a path that will take it near a planet. We know this object is in orbit around the planet if this path is a(an):

Accepted Answer

A) helix. 
B) ellipse. 
C) hyperbola. 
D) parabola. 
A) helix. 
B) ellipse. 
C) hyperbola. 
D) parabola.

Question 16

In an ellipse, the semimajor axis is a distance measured:

Accepted Answer

A) along the circumference between the closest point to and the farthest point from one focus. 
B) along the shorter diameter from the center to the ellipse. 
C) from focus to focus. 
D) along the longer diameter from the center through one focus to the ellipse. 
A) along the circumference between the closest point to and the farthest point from one focus. 
B) along the shorter diameter from the center to the ellipse. 
C) from focus to focus. 
D) along the longer diameter from the center through one focus to the ellipse.

Question 17

The sidereal periods of the following outer planets, from shortest to longest, are:

Accepted Answer

A) Jupiter, Saturn, and Uranus. 
B) Uranus, Saturn, and Jupiter. 
C) Saturn, Uranus, and Jupiter. 
D) There is no simple relationship among the sidereal periods of these planets. 
A) Jupiter, Saturn, and Uranus. 
B) Uranus, Saturn, and Jupiter. 
C) Saturn, Uranus, and Jupiter. 
D) There is no simple relationship among the sidereal periods of these planets.

Question 18

Copernicus's model for planetary motion:

Accepted Answer

A) got rid of epicycles entirely. 
B) retained epicycles to reproduce retrograde motion. 
C) retained epicycles to reproduce the observed variations in the speeds of the planets along their orbits. 
D) retained epicycles but made them elliptical. 
A) got rid of epicycles entirely. 
B) retained epicycles to reproduce retrograde motion. 
C) retained epicycles to reproduce the observed variations in the speeds of the planets along their orbits. 
D) retained epicycles but made them elliptical.

Question 19

The synodic periods of the following outer planets, from shortest to longest, are:

Accepted Answer

A) Jupiter, Saturn, and Uranus. 
B) Uranus, Saturn, and Jupiter. 
C) Saturn, Uranus, and Jupiter. 
D) There is no simple relationship among the synodic periods of these planets. 
A) Jupiter, Saturn, and Uranus. 
B) Uranus, Saturn, and Jupiter. 
C) Saturn, Uranus, and Jupiter. 
D) There is no simple relationship among the synodic periods of these planets.

Question 20

The escape speed of an object from Earth depends on each of the following except one. Which does it not depend upon?

Accepted Answer

A) the mass of the object 
B) the universal gravitational constant 
C) the mass of Earth 
D) the radius of Earth 
A) the mass of the object 
B) the universal gravitational constant 
C) the mass of Earth 
D) the radius of Earth

Exam 4: Gravitation and the Waltz of the Planets

How does the speed of a communications satellite vary as it moves around Earth?

At what position in its orbit will an inferior planet appear to be moving, for a day or two, more or less directly toward Earth? (See Figure 4-6 of Universe, 11th ed., and draw a diagram if it will help.) ​ ​

As a spacecraft such as Voyager 2 moves away from the Sun, the gravitational force on it F varies with distance R from the Sun in which mathematical way? ( means "proportional to.")

Which of the following situations is not an acceptable orbital path for a body gravitationally bound to the Sun?

Two objects of different mass when dropped by an astronaut on the Moon have:

How many more orbits around the Sun in 1 synodic period of that planet does an inferior planet cover compared to Earth?

The sidereal period of Mars is 1.9 years. Use the appropriate formula in Box 4-1 to find the time from the middle of one retrograde loop for Mars to the middle of the next retrograde loop (assuming circular orbits for Mars and Earth). This time is:

Does the Sun or the Moon have a greater effect in causing the tides on Earth?

An imaginary planet is orbiting the Sun in a circle at precisely the same average orbital distance as Earth (i.e., 1 au). What is its sidereal period?

Halley's Comet returns to the Sun's vicinity every 76 years in an elliptical orbit. What is the semimajor axis of this orbit?

Two spacecrafts that have different masses but rocket engines of identical force are at rest in space. If they fire their rockets at the same time, which ship will speed up fastest?

The gravitational pull of the Sun on the Moon is stronger than the gravitational pull of Earth on the Moon. Which of these is more important in raising tides on the Moon?

The Ptolemaic model of the universe included each of the following features, except one. Which one is the exception?

A small object is on a path that will take it near a planet. We know this object is in orbit around the planet if this path is a(an):

In an ellipse, the semimajor axis is a distance measured:

The sidereal periods of the following outer planets, from shortest to longest, are:

Copernicus's model for planetary motion:

The synodic periods of the following outer planets, from shortest to longest, are:

The escape speed of an object from Earth depends on each of the following except one. Which does it not depend upon?

Astronomy and the Universe

Knowing the Heavens

Eclipses and the Motion of the Moon

The Nature of Light

Optics and Telescopes

Comparative Planetology I: Our Solar System

Comparative Planetology II: the Origin of Our Solar System

The Living Earth

Our Barren Moon

Mercury, Venus, and Mars: Terrestrial, yet Unique

Jupiter and Saturn: Lords of the Planets

Jupiter and Saturns Satellites of Fire and Ice

Uranus, Neptune, Pluto, and the Kuiper Belt: Remote Worlds

Asteroids, Comets, and Impacts

Our Star, the Sun

The Nature of the Stars

The Birth of Stars

Stellar Evolution: on and After the Main Sequence

Stellar Evolution: The Death of Stars

Stellar Remnants: Neutron Stars and Black Holes

Our Galaxy

Galaxies

Quasars and Active Galaxies

Cosmology: The Origin and Evolution of the Universe

Exploring the Early Universe

The Search for Extraterrestrial Life

Filters

At what position in its orbit will an inferior planet appear to be moving, for a day or two, more or less directly toward Earth? (See Figure 4-6 of Universe, 11th ed., and draw a diagram if it will help.)