Question 1

Explain why Saturn's rings do not clump together to form a moon.

Accepted Answer

Saturn's rings orbit within th

Question 2

Explain why the gravitational force an object experiences from Earth can be considered to come from the center of Earth.

Accepted Answer

Each part of Earth pulls on the object b

Question 3

According to the figure below, neap tides occur when the lunar and solar tides ________, resulting in ________ tides.

Accepted Answer

A)  add; above-average 
B)  partially cancel out; above-average 
C)  add; below-average 
D)  partially cancel out; below-average 
E)  completely cancel out; no 
A)  add; above-average 
B)  partially cancel out; above-average 
C)  add; below-average 
D)  partially cancel out; below-average 
E)  completely cancel out; no

Question 4

According to the figure below, spring tides occur when the lunar and solar tides ________, resulting in ________ tides.

Accepted Answer

A)  add; above-average 
B)  partially cancel out; above-average 
C)  add; below-average 
D)  partially cancel out; below-average 
E)  completely cancel out; no 
A)  add; above-average 
B)  partially cancel out; above-average 
C)  add; below-average 
D)  partially cancel out; below-average 
E)  completely cancel out; no

Question 5

When one object is tidally locked to the larger object it is orbiting, it

Accepted Answer

A)  will be destroyed by tidal forces. 
B)  will be ejected from its orbit soon after. 
C)  experiences 2 high tides at every location per single rotation. 
D)  will have increased self-gravity, making it close to a perfect sphere. 
E)  rotates exactly once during each orbit. 
A)  will be destroyed by tidal forces. 
B)  will be ejected from its orbit soon after. 
C)  experiences 2 high tides at every location per single rotation. 
D)  will have increased self-gravity, making it close to a perfect sphere. 
E)  rotates exactly once during each orbit.

Question 6

Explain what the Roche limit is and how it is related to rings around giant planets.

Accepted Answer

The Roche limit is the distance from a l

Question 7

If you have two moons that have the same radius, but Moon A is denser and has 2 times the mass of Moon B, how do their escape velocities from their respective surfaces compare?

Accepted Answer

A)  Moon A has an escape velocity that is 1.4 times larger than Moon B. 
B)  Moon A has an escape velocity that is 1.4 times smaller than Moon B. 
C)  Moon A has an escape velocity that is 2 times smaller than Moon B. 
D)  Moon A has an escape velocity that is 2 times larger than Moon B. 
E)  Because gravity affects all masses the same, the escape velocities are the same. 
A)  Moon A has an escape velocity that is 1.4 times larger than Moon B. 
B)  Moon A has an escape velocity that is 1.4 times smaller than Moon B. 
C)  Moon A has an escape velocity that is 2 times smaller than Moon B. 
D)  Moon A has an escape velocity that is 2 times larger than Moon B. 
E)  Because gravity affects all masses the same, the escape velocities are the same.

Question 8

Titan, the largest moon of Saturn, has an orbital period of 16 days and a semimajor axis of 1.2 *109 m.Based on this information, what is Saturn's mass? For reference, Earth's mass is
6 * 1024 kg.

Accepted Answer

A)  290 MEarth 
B)  130 MEarth 
C)  90 MEarth 
D)  40 MEarth 
E)  4 MEarth 
A)  290 MEarth 
B)  130 MEarth 
C)  90 MEarth 
D)  40 MEarth 
E)  4 MEarth

Question 9

According to the figure below, the approximate amount of time between two high tides at a given location is about

Accepted Answer

A)  3 hours. 
B)  8 hours. 
C)  6 hours. 
D)  12 hours. 
E)  24 hours. 
A)  3 hours. 
B)  8 hours. 
C)  6 hours. 
D)  12 hours. 
E)  24 hours.

Question 10

Which of the statements below is true about the Roche limit of a giant planet?

Accepted Answer

A)  It is about equal to the radius of the planet. 
B)  It is the closest to the planet that moons normally are found. 
C)  It is the closest to the planet that rings will be found. 
D)  It is the farthest from the planet that moons normally are found. 
E)  Because they have no solid surfaces, giant planets do not have a Roche limit. 
A)  It is about equal to the radius of the planet. 
B)  It is the closest to the planet that moons normally are found. 
C)  It is the closest to the planet that rings will be found. 
D)  It is the farthest from the planet that moons normally are found. 
E)  Because they have no solid surfaces, giant planets do not have a Roche limit.

Question 11

According to the figure below, the approximate amount of time between a high tide and a low tide at a given location is about

Accepted Answer

A)  3 hours. 
B)  8 hours. 
C)  6 hours. 
D)  12 hours. 
E)  24 hours. 
A)  3 hours. 
B)  8 hours. 
C)  6 hours. 
D)  12 hours. 
E)  24 hours.

Question 12

Between any two objects with mass, the force of gravity is always

Accepted Answer

A)  different for each mass. 
B)  the same value, regardless of the masses involved. 
C)  attractive. 
D)  a fictitious force. 
E)  repulsive. 
A)  different for each mass. 
B)  the same value, regardless of the masses involved. 
C)  attractive. 
D)  a fictitious force. 
E)  repulsive.

Question 13

Because of tidal forces, for every ________ time(s) it rotates on its axis, Mercury revolves around the Sun ________ time(s).

Accepted Answer

A)  1; 1 
B)  2; 3 
C)  3; 2 
D)  10; 1 
E)  20; 1 
A)  1; 1 
B)  2; 3 
C)  3; 2 
D)  10; 1 
E)  20; 1

Question 14

Explain the origin of tidal forces on Earth due to the Moon.

Accepted Answer

Because Earth is a real object with size

Question 15

For which of the following orbital velocities, V, is the orbit unbound?

Accepted Answer

A)  V just below escape velocity 
B)  V = circular velocity 
C)  V$\gt$ escape velocity 
D)  V  $\lt$escape velocity 
E)  V = 0 
A)  V just below escape velocity 
B)  V = circular velocity 
C)  V$\gt$ escape velocity 
D)  V  $\lt$escape velocity 
E)  V = 0

Question 16

Two rocks (call them S and T) are a distance of 50 km from one another in empty space.Rock S has 20 times the mass of rock T.Considering only their mutual gravitational force, which rock will accelerate faster in response to gravity?

Accepted Answer

A)  rock S 
B)  rock T 
C)  Both rocks will have the same acceleration. 
D)  Neither rock will accelerate. 
E)  Not enough information is available to answer. 
A)  rock S 
B)  rock T 
C)  Both rocks will have the same acceleration. 
D)  Neither rock will accelerate. 
E)  Not enough information is available to answer.

Question 17

Because of tidal forces, which type of eclipse will become impossible first?

Accepted Answer

A)  partial lunar 
B)  total lunar 
C)  partial solar 
D)  total solar 
E)  annular solar 
A)  partial lunar 
B)  total lunar 
C)  partial solar 
D)  total solar 
E)  annular solar

Question 18

If we wanted to increase the Hubble Space Telescope's altitude above Earth and keep it in a stable orbit, we also would need to

Accepted Answer

A)  increase its orbital speed. 
B)  increase its weight. 
C)  decrease its weight. 
D)  decrease its orbital speed. 
E)  increase its mass. 
A)  increase its orbital speed. 
B)  increase its weight. 
C)  decrease its weight. 
D)  decrease its orbital speed. 
E)  increase its mass.

Question 19

The Hubble Space Telescope orbits at an altitude of 600 km above Earth's surface.Assuming it is in a stable circular orbit, what is its velocity? For reference, Earth's radius is 6,400 km and Earth's mass is 6* 1024 kg.

Accepted Answer

A)  240,000 m/s 
B)  7,500 m/s 
C)  51,000 m/s 
D)  64,000 m/s 
E)  You also must know the mass of the Hubble Space Telescope to determine its speed. 
A)  240,000 m/s 
B)  7,500 m/s 
C)  51,000 m/s 
D)  64,000 m/s 
E)  You also must know the mass of the Hubble Space Telescope to determine its speed.

Question 20

The distance between Earth and the Moon is increasing because of

Accepted Answer

A)  the expansion of the universe. 
B)  the expansion of the Solar System. 
C)  tidal forces from the Moon. 
D)  tidal forces from the Moon and Sun. 
E)  dark energy. 
A)  the expansion of the universe. 
B)  the expansion of the Solar System. 
C)  tidal forces from the Moon. 
D)  tidal forces from the Moon and Sun. 
E)  dark energy.

Exam 4: Gravity and Orbits

Explain why Saturn's rings do not clump together to form a moon.

Explain why the gravitational force an object experiences from Earth can be considered to come from the center of Earth.

According to the figure below, neap tides occur when the lunar and solar tides ________, resulting in ________ tides.

According to the figure below, spring tides occur when the lunar and solar tides ________, resulting in ________ tides.

When one object is tidally locked to the larger object it is orbiting, it

Explain what the Roche limit is and how it is related to rings around giant planets.

If you have two moons that have the same radius, but Moon A is denser and has 2 times the mass of Moon B, how do their escape velocities from their respective surfaces compare?

Titan, the largest moon of Saturn, has an orbital period of 16 days and a semimajor axis of 1.2 *109 m.Based on this information, what is Saturn's mass? For reference, Earth's mass is 6 * 1024 kg.

According to the figure below, the approximate amount of time between two high tides at a given location is about

Which of the statements below is true about the Roche limit of a giant planet?

According to the figure below, the approximate amount of time between a high tide and a low tide at a given location is about

Between any two objects with mass, the force of gravity is always

Because of tidal forces, for every ________ time(s) it rotates on its axis, Mercury revolves around the Sun ________ time(s).

Explain the origin of tidal forces on Earth due to the Moon.

For which of the following orbital velocities, V, is the orbit unbound?

Two rocks (call them S and T) are a distance of 50 km from one another in empty space.Rock S has 20 times the mass of rock T.Considering only their mutual gravitational force, which rock will accelerate faster in response to gravity?

Because of tidal forces, which type of eclipse will become impossible first?

If we wanted to increase the Hubble Space Telescope's altitude above Earth and keep it in a stable orbit, we also would need to

The Hubble Space Telescope orbits at an altitude of 600 km above Earth's surface.Assuming it is in a stable circular orbit, what is its velocity? For reference, Earth's radius is 6,400 km and Earth's mass is 6* 1024 kg.

The distance between Earth and the Moon is increasing because of

Thinking Like an Astronomer

Patterns in the Skymotions of Earth and the Moon

Motion of Astronomical Bodies

Light

The Tools of the Astronomer

The Formation of Planetary Systems

The Terrestrial Planets and Earths Moon

Atmospheres of the Terrestrial Planets

Worlds of Gas and Liquidthe Giant Planets

Planetary Moons and Rings

Dwarf Planets and Small Solar System Bodies

Taking the Measure of Stars

Our Starthe Sun

The Interstellar Medium and Star Formation

Evolution of Low-Mass Stars

Evolution of High-Mass Stars

Relativity and Black Holes

Galaxies

The Milky Waya Normal Spiral Galaxy

The Expanding Universe

Cosmology

Large-Scale Structure in the Universe

Life

Filters

According to the figure below, neap tides occur when the lunar and solar tides , resulting in tides.

According to the figure below, spring tides occur when the lunar and solar tides , resulting in tides.

Titan, the largest moon of Saturn, has an orbital period of 16 days and a semimajor axis of 1.2 10⁹ m.Based on this information, what is Saturn's mass? For reference, Earth's mass is 6 10²⁴ kg.

Because of tidal forces, for every time(s) it rotates on its axis, Mercury revolves around the Sun time(s).

The Hubble Space Telescope orbits at an altitude of 600 km above Earth's surface.Assuming it is in a stable circular orbit, what is its velocity? For reference, Earth's radius is 6,400 km and Earth's mass is 6* 10²⁴ kg.