Deck 3: Motion of Astronomical Bodies

Question 1

Retrograde motion is seen when ____________ due to the Earth's motion.

A) stars change their position in the sky with respect to background stars
B) stars rise in the west and set in the east
C) planets rise in the west and set in the east
D) planets change the direction in which they wander across the night sky
E) planets orbit the Sun in the opposite direction

Answer 1

planets change the direction in which they wander across the night sky

Question 2

Kepler's third law written as P² =A³ holds true mathematically for our Solar System only if the period is expressed in years and the semimajor axis is expressed in AU.

Answer 2

True

Question 3

Newton's second law says that more massive objects are accelerated more than less massive objects when the same force is applied.

Answer 3

False

Question 4

How did Ptolemy "fix" the geocentric system?

A) He introduced retrograde motion.
B) He introduced prograde motion.
C) He moved the Sun to the center.
D) He introduced epicycles.
E) He introduced Earth's motion.

Question 5

When the geocentric model of the solar system did not match the observed positions of the planets:

A) Tycho Brahe made measurements of higher accuracy and showed the geocentric model was correct
B) Ptolemy added epicycles to the geocentric model to match the observed data
C) Galileo argued that the Sun revolved around the Earth
D) Kepler was inspired to create the theory of gravity
E) Copernicus proposed the heliocentric mode

Question 6

Based on his observations of the planets, Copernicus calculated the relative distance of the planets from the Sun using the heliocentric model, and these distances were:

A) 10 times too large
B) exactly correct
C) close to the correct values, with errors less than 0.5 AU
D) accurate, but not as accurate as Ptolemy's values
E) two times too small

Question 7

An inferior planet is one that is:

A) smaller than Earth
B) larger than Earth
C) closer to the Sun than Earth
D) farther from the Sun than Earth
E) made of lighter materials than Earth

Question 8

In the heliocentric system, retrograde motion is not an actual motion of the planet but appears to occur because of the Earth's movement.

Question 9

At the center of the geocentric model of the Solar System is the:

A) Sun
B) Moon
C) Earth
D) Venus
E) Jupiter

Question 10

Planets with circular orbits travel at the same speed at all points in their orbits, whereas planets with elliptical orbits change their speeds at different points in their orbits.

Question 11

Even though they move at faster average speeds, the outer planets in the Solar System have longer periods than the inner planets.

Question 12

Which of the following are the inferior planets?

A) Mercury
B) Mercury and Mars
C) Mercury and Venus
D) Mars
E) Mercury, Mars, and Pluto

Question 13

A planet travels fastest in its orbit when it is closest to the Sun.

Question 14

Planets orbit the Sun on circular orbits.

Question 15

Which of the following are superior planets?

A) Mars
B) Earth and Venus
C) Venus, Mars, Jupiter, and Saturn
D) Earth, Jupiter, and Saturn
E) Mars, Jupiter, and Saturn

Question 16

Who of the following was NOT a proponent of the heliocentric model of the solar system?

A) Galileo
B) Copernicus
C) Newton
D) Ptolemy
E) Aristarchus

Question 17

Nicolaus Copernicus was the first to propose that Earth revolved around the Sun.

Question 18

_________ was the first person to introduce a mathematical heliocentric model of the Solar System from which accurate predictions could be made of planets' positions.

A) Nicolaus Copernicus
B) Tycho Brahe
C) Johannes Kepler
D) Galileo Galilei
E) Isaac Newton

Question 19

Johannes Kepler obtained accurate data on the positions of the planets in the sky over time, which Galileo used to prove that planets revolved around the Sun.

Question 20

As we move farther from the Sun, the circumferences of planetary orbits are larger, and the speeds at which planets travel increase.

Question 21

In the ________ model of the Solar System, ________ motion is only an apparent, not a real, motion.

A) geocentric; retrograde
B) heliocentric; retrograde
C) geocentric; prograde
D) heliocentric; prograde
E) Galilean; prograde

Question 22

If the synodic period of Mars is observed from Earth to be 2.1 years, what is Mars's sidereal period?

A) 5.3 years
B) 0.47 years
C) 1.9 years
D) 3.4 years
E) 0.69 years

Question 23

Observations of what astronomical events allowed astronomers to definitively determine that the heliocentric model of the solar system was correct?

A) total eclipses of the Sun
B) the precise motions of planets across the celestial sphere
C) motion of bright stars on the celestial sphere
D) the timing of the equinoxes
E) the timing of the solstices

Question 24

The time it takes for a planet to come back to the same position relative to the Sun is called its _________ period.

A) synodic
B) sidereal
C) heliocentric
D) geocentric
E) prograde

Question 25

The fact that Kepler's heliocentric model of the Solar System predicted _________ more easily and accurately than the geocentric model is an illustration of how scientific theories evolve by the scientific method.

A) solar eclipses
B) lunar eclipses
C) retrograde motion of planets
D) prograde motion of planets
E) the duration of the seasons

Question 26

When the Sun, the Earth, and a planet all lie along a straight line, the planet is at:

A) quadrature
B) opposition
C) greatest elongation
D) conjunction
E) either opposition or conjunction

Question 27

If the synodic period of Venus is observed from Earth to be 1.6 years, Venus' sidereal period is _____ years.

A) 1.9 years
B) 0.45 years
C) 0.28 years
D) 1.6 years
E) 0.62 years

Question 28

The amount of time a planet takes to orbit the Sun is called its _________ period.

A) synodic
B) sidereal
C) prograde
D) retrograde
E) geocentric

Question 29

An empirical science is one that is based on:

A) assumptions
B) calculus
C) computer models
D) observed data
E) hypotheses

Question 30

You find a moon orbiting a planet and you measure the distance between the moon and the planet once a night over the course of a few weeks. Its behavior is shown in the figure below where the time shown is the time since your first observation. What is this moon's orbital period?

A) 22 days
B) 20 days
C) 18 days
D) 11 days
E) 6 days

Question 31

Figure 1
Based on Figure 1, a superior planet at opposition:

A) would rise at noon and set at midnight
B) would rise at midnight and set at noon
C) would rise at sunset and set at sunrise
D) would rise at sunrise and set at sunrise
E) would rise at 8 and set at 8

Question 32

Which laws are based entirely on observational data without having any theoretical framework behind them?

A) physical laws
B) Galileo's laws of planetary motion
C) Newton's laws of motion
D) deductive laws
E) empirical laws

Question 33

Figure 1
Based on Figure 1, a superior planet would be seen high overhead at midnight:

A) when at opposition
B) when at eastern quadrature
C) when at conjunction
D) when at western quadrature
E) throughout its orbit

Question 34

If a superior planet is observed from Earth to have a synodic period of 1.2 years, what is its sidereal period?

A) 0.54 years
B) 1.8 years
C) 2.3 years
D) 4.0 years
E) 6.0 years

Question 35

Based on the figure below, an inferior planet would be farthest from the Sun and therefore most easily visible at:

A) inferior conjunction
B) superior conjunction
C) greatest eastern elongation
D) greatest western elongation
E) at either greatest eastern or western elongation

Question 36

If the sidereal period of Jupiter is 11.9 years, what is Jupiter's synodic period as observed from Earth?

A) 2.3 years
B) 0.84 years
C) 0.92 years
D) 1.09 years
E) 1.5 years

Question 37

A superior planet is one that is:

A) smaller than Earth
B) larger than Earth
C) closer to the Sun than Earth
D) farther from the Sun than Earth
E) made of heavier materials than Earth

Question 38

When the Earth catches up to a slower moving outer planet and passes it like a faster runner overtaking a slower runner in an outside lane, the planet:

A) exhibits retrograde motion
B) slows down because it feels the Earth's gravitational pull
C) decreases in brightness as it passes through the Earth's shadow
D) moves into a more elliptical orbit
E) exhibits prograde motion

Question 39

The time it takes a planet to complete one full orbital revolution is commonly known as its:

A) period
B) frequency
C) orbital domain
D) velocity
E) eccentricity

Question 40

Astronomers argued that the heliocentric model of the Solar System was simpler than the geocentric model, based on:

A) the observation that the planets do not move relative to the background stars
B) the fact that the Moon orbits the Earth
C) the fact that the Sun is more massive than the Earth
D) the observed retrograde motions of the planets
E) the observed timing of lunar and solar eclipses

Question 41

Kepler's third law is a relationship between an orbiting object's:

A) gravitational force and mass
B) acceleration and mass
C) velocity and period
D) period and semimajor axis
E) semimajor axis and velocity

Question 42

A circle has an eccentricity of _________ and a line has an eccentricity of _________.

A) 1; 0
B) 1; 1
C) 0; infinity
D) 0; 1
E) infinity; 0

Question 43

Suppose an asteroid had an orbit with a semimajor axis of 4 AU. How long would it take for it to orbit once around the Sun?

A) 76 years
B) 45 years
C) 8 years
D) 16 years
E) 2 years

Question 44

Which of the following is TRUE about a comet that is on an elliptical orbit around the Sun?

A) The comet's speed is greatest when it is farthest from the Sun.
B) The comet's speed is greatest when it is nearest the Sun.
C) This comet's speed is zero.
D) The comet's speed is constant because its mass and the Sun's mass stay approximately the same.
E) The eccentricity is very low.

Question 45

The eccentricity of the majority of the planetary orbits in our Solar System is approximately:

A) 0
B) 1
C) 0.5
D) 0.2
E) infinity

Question 46

If Jupiter has an orbital period of 12 years, what value is closest to its average distance from the Sun?

A) 2 AU
B) 25 AU
C) 10 AU
D) 5 AU
E) 144 AU

Question 47

Figure 2
In Figure 2, a planet orbits the Sun. During which of the three sections (A, B, or C) will the planet have the lowest average velocity?

A) A
B) B
C) C
D) The average velocity is the same for sections A, B, and C.
E) The information given is insufficient to answer this question.

Question 48

A comet orbits the Sun with a semimajor axis of 90 AU. Using Kepler's third law, the comet's orbital period is approximately

A) 850 years
B) 630 years
C) 410 years
D) 180 years
E) 90 years

Question 49

During a certain comet's orbit around the Sun, its closest distance to the Sun is 0.6 AU, and its farthest distance from the Sun is 35 AU. At what distance will the comet's orbital velocity be the largest?

A) 35 AU
B) 17.8 AU
C) 1.2 AU
D) 0.6 AU
E) The comet's velocity is constant no matter what its distance is.

Question 50

Which equation represents the relationship of the planet's period to its semimajor axis in data shown in the figure below?

A) P = A
B) P² = A²
C) P³ = A²
D) P² = A³
E) P= A³

Question 51

Galileo's telescopic observations of _________ led him to conclude that the heliocentric model of the Solar System was correct.

A) motion of Jupiter and Saturn
B) motion of Venus
C) moons of Jupiter and phases of Venus
D) phases of the Moon
E) epicycles of Mars

Question 52

Kepler's third law for our Solar System can be expressed mathematically as:

A) P = A
B) P² = A²
C) P² = A³
D) P³= A²
E) P = A²

Question 53

If Neptune has a semimajor axis of 19 AU, its orbital period is:

A) 45 years
B) 83 years
C) 130 years
D) 220 years
E) 380 years

Question 54

Kepler's third law says that a comet with a period of 160 years will have a semimajor axis of:

A) 30 AU
B) 50 AU
C) 90 AU
D) 140 AU
E) 210 AU

Question 55

Figure 2

-In Figure 2, a planet orbits the Sun. The line connecting the planet and Sun sweeps out three areas labeled A, B, and C, during three different time intervals. If the duration of the time intervals are the same (meaning t₂ -t₁ = t₄ -t₃ = t₆ - t₅), how are the sizes of these areas related?

A) A $\gt$ B $\gt$ C
B) C $\gt$ B $\gt$ A
C) A $\gt$ C $\gt$ B
D) B $\gt$ A $\gt$ C
E) A, B, and C have the same size.

Question 56

If the Sun is located at one focus of Earth's elliptical orbit, what is at the other focus?

A) Earth
B) the Moon
C) another planet
D) nothing
E) Jupiter

Question 57

If Mercury has an orbital period of about 88 days, what is its average distance from the Sun?

A) 0.2 AU
B) 0.01 AU
C) 0.05 AU
D) 0.4 AU
E) 0.7 AU

Question 58

The dwarf planet named Eris orbits the Sun with a semimajor axis of 68 AU. Using Kepler's third law, Eris's orbital period is:

A) 26 years
B) 130 years
C) 72 years
D) 240 years
E) 560 years

Question 59

Kepler's second law says that if a planet is in an elliptical orbit around a star, then the planet moves fastest when the planet is:

A) farthest from the star
B) closest to the star
C) exceeding the escape velocity
D) experiencing zero acceleration
E) located at one of the foci

Question 60

The average distance between a planet and the Sun is given by the _________ of its elliptical orbit.

A) radius
B) semiminor axis
C) eccentricity
D) semimajor axis
E) distance between the foci

Question 61

Who was the first notable historical figure to argue that the Earth orbits the Sun? Name two other people that were instrumental in arguing for the heliocentric model.

Question 62

Assume that at sunset today, Jupiter appears to be 20 degrees away from the Sun. If the sidereal period of Jupiter is 12 years, when will it next appear exactly in this same position relative to the Sun?

Question 63

If you start from rest and accelerate at 10 mph/s and end up traveling at 60 mph, how long did it take?

A) 1 seconds
B) 6 seconds
C) 600 seconds
D) 0.6 seconds
E) 200 seconds

Question 64

Explain how the synodic and sidereal periods of a planet are defined. Why are they not the same? Explain how they are related to one another.

Question 65

If you travel 20 miles from home to school in 30 minutes, what is your average velocity?

A) 20 mph
B) 40 mph
C) 0.7 mph
D) 5 mph
E) 600 mph

Question 66

Explain how the Occam's razor argument influenced whether people believed in the heliocentric or the geocentric model of the Solar System.

Question 67

The natural tendency of an object to resist changes in motion is called:

A) inertia
B) weight
C) acceleration
D) mass
E) velocity

Question 68

If you apply a force of 10 N to a grocery cart and get an acceleration of 0.5 m/s², then the mass of the grocery cart is:

A) 5 kg
B) 0.05 kg
C) 20 kg
D) 50 kg
E) 0.20 kg

Question 69

If a 100-kg astronaut pushes on a 5,000-kg satellite and the satellite experiences an acceleration of 0.1 m/s², what is the acceleration experienced by the astronaut in the opposite direction?

A) 5 m/s²
B) 10 m/s²
C) 50 m/s²
D) 0.1 m/s²
E) 1000 m/s²

Question 70

Based on the figure shown below, explain why an inferior planet would not be able to be seen at all from Earth when it is in conjunction.

Question 71

Figure 3
Based on Figure 3, explain why, when a superior planet is in opposition, it will be visible from Earth all night long.

Question 72

If you travel at a velocity of 30 mph during a 15-mile trip from home to school, how long does the trip take?

A) 2 hours
B) 0.2 hours
C) 0.5 hours
D) 5 hours
E) 750 hours

Question 73

If you travel at a velocity of 60 mph for a 5-hour trip, how far did you travel?

A) 300 miles
B) 120 miles
C) 12 miles
D) 0.4 miles
E) 240 mph

Question 74

What is your acceleration if you go from 0 to 60 mph in 4 seconds?

A) 60 mph/s
B) 30 mph/s
C) 15 mph/s
D) 8.5 mph/s
E) 240 mph/s

Question 75

If you start from rest and accelerate at 15 mph/s for 5 seconds, how fast will you be traveling at the end?

A) 75 mph
B) 45 mph
C) 3 mph
D) 12 mph
E) 20 mph

Question 76

You apply a force of 10 N to a grocery cart in order to get an acceleration of 0.5 m/s². If you apply a force of 20 N to the same grocery cart, its acceleration will be:

A) 10 m/s²
B) 1 m/s²
C) 0.5 m/s²
D) 0.25m/s²
E) 20 m/s²

Question 77

Newton's first law states that objects in motion:

A) eventually come to rest
B) experience an unbalanced force
C) experience a nonzero acceleration
D) stay in motion
E) must be subject to zero friction

Question 78

Why were epicycles used in the geocentric system? Who first introduced epicycles?

Question 79

Based on the figure shown below, explain why an inferior planet is most likely to be seen when it is at one of its greatest elongations.

Question 80

Figure 3
Based on Figure 3, explain why a superior planet, when it is at conjunction, will not be seen at all from Earth during the night.