Question 1

If Earth did not have a moon, would we still have tides because of the Sun? If so, explain how they might be different, or why they might remain unchanged.

Accepted Answer

If Earth did not have a moon,Earth would

Question 2

Earth is held together in the shape of a sphere.This is due to

Accepted Answer

A)  chemical bonds. 
B)  pressure from the Sun. 
C)  its rotation rate. 
D)  tidal forces. 
E)  its self-gravity. 
A)  chemical bonds. 
B)  pressure from the Sun. 
C)  its rotation rate. 
D)  tidal forces. 
E)  its self-gravity.

Question 3

Two rocks (call them S and T) are released at the same time from the same height and start from rest.Rock S has 20 times the mass of rock T.Which rock will fall faster if the only forces involved are each rock's mutual gravitational attraction with Earth?

Accepted Answer

A)  rock S 
B)  rock T 
C)  Both rocks will fall at the same rate. 
D)  Not enough information is available to answer. 
E)  Neither rock will fall, because they will remain at rest. 
A)  rock S 
B)  rock T 
C)  Both rocks will fall at the same rate. 
D)  Not enough information is available to answer. 
E)  Neither rock will fall, because they will remain at rest.

Question 4

Suppose you are suddenly transported to a planet that had 1/4 the radius of Earth but the same mass as Earth.Your weight would ________ by a factor of ________.

Accepted Answer

A)  increase; 4 
B)  increase; 16 
C)  decrease; 4 
D)  decrease; 16 
E)  decrease; 8 
A)  increase; 4 
B)  increase; 16 
C)  decrease; 4 
D)  decrease; 16 
E)  decrease; 8

Question 5

Which of the following is an unbound orbit?

Accepted Answer

A)  elliptical 
B)  hyperbolic 
C)  circular 
D)  All of these are unbound orbits. 
E)  None of these are unbound orbits. 
A)  elliptical 
B)  hyperbolic 
C)  circular 
D)  All of these are unbound orbits. 
E)  None of these are unbound orbits.

Question 6

What is the escape velocity from Mars if its mass is 6 *1023 kg and its radius is 3,400 km?

Accepted Answer

A)  2,400 m/s 
B)  4,900 m/s 
C)  8,600 km/s 
D)  12,000 m/s 
E)  25,000 km/s 
A)  2,400 m/s 
B)  4,900 m/s 
C)  8,600 km/s 
D)  12,000 m/s 
E)  25,000 km/s

Question 7

Why are there high and low tides each day instead of having the same tide all day during a given phase of the Moon?

Accepted Answer

There are high and l

Question 8

If you doubled the distance the Moon is from Earth, by what fraction does the strength of the tidal force change?

Accepted Answer

A)  2 
B)  1/2 
C)  1/4 
D)  1/8 
E)  1/16 
A)  2 
B)  1/2 
C)  1/4 
D)  1/8 
E)  1/16

Question 9

Earth's rotation rate is slowing because of

Accepted Answer

A)  radioactive decay in its core. 
B)  relativistic effects of gravity. 
C)  tidal forces from the Moon. 
D)  the gravitational force of the Sun. 
E)  gravitational drag from dark matter. 
A)  radioactive decay in its core. 
B)  relativistic effects of gravity. 
C)  tidal forces from the Moon. 
D)  the gravitational force of the Sun. 
E)  gravitational drag from dark matter.

Question 10

According to the figure below, when the Moon is in between Earth and the Sun, ________ tides occur.

Accepted Answer

A)  spring 
B)  no 
C)  neap 
D)  high 
E)  low 
A)  spring 
B)  no 
C)  neap 
D)  high 
E)  low

Question 11

Which of the following is true considering Newton's laws of motion and Newton's law of gravitation?

Accepted Answer

A)  They disprove Galileo's law of inertia. 
B)  They only work when describing perfectly circular orbits. 
C)  They support a geocentric Solar System. 
D)  They can be used to produce Kepler's three laws. 
E)  They are only valid in deep space. 
A)  They disprove Galileo's law of inertia. 
B)  They only work when describing perfectly circular orbits. 
C)  They support a geocentric Solar System. 
D)  They can be used to produce Kepler's three laws. 
E)  They are only valid in deep space.

Question 12

Astronauts orbiting Earth in the space shuttle experience so-called weightlessness in space because

Accepted Answer

A)  they are farther away from Earth. 
B)  of centrifugal force. 
C)  the gravitational pull of the Moon counteracts Earth's gravitational pull. 
D)  they are in constant free fall around Earth. 
E)  they are in space where there is no gravity. 
A)  they are farther away from Earth. 
B)  of centrifugal force. 
C)  the gravitational pull of the Moon counteracts Earth's gravitational pull. 
D)  they are in constant free fall around Earth. 
E)  they are in space where there is no gravity.

Question 13

Explain why the Moon rotates in the same amount of time as it takes to orbit once around Earth.

Accepted Answer

The Moon's tidal locking is ca

Question 14

If an object is in orbit with an orbital speed less than the escape speed but greater than the circular orbit speed, what type of orbit is it?

Accepted Answer

A)  elliptical 
B)  hyperbolic 
C)  circular 
D)  parabolic 
E)  none of these 
A)  elliptical 
B)  hyperbolic 
C)  circular 
D)  parabolic 
E)  none of these

Question 15

Mars has about one-tenth the mass of Earth and half Earth's radius.By what numerical factor does the acceleration of gravity on Mars compare to that on Earth?

Accepted Answer

g = GM/R²; thus g_M

Question 16

What is the escape velocity from Ceres if its mass is 9 * 1020 kg and its radius is 470 km?

Accepted Answer

A)  98 km/s 
B)  200 km/s 
C)  340 m/s 
D)  500 m/s 
E)  12,400 m/s 
A)  98 km/s 
B)  200 km/s 
C)  340 m/s 
D)  500 m/s 
E)  12,400 m/s

Question 17

When the Sun and Moon are separated by 90 degrees in the sky, ________ tides occur on Earth when the strength of the tides are ________ than normal.

Accepted Answer

A)  spring; lower 
B)  spring; higher 
C)  lunar; lower 
D)  neap; lower 
E)  neap; higher 
A)  spring; lower 
B)  spring; higher 
C)  lunar; lower 
D)  neap; lower 
E)  neap; higher

Question 18

The definition of the term satellite in astronomy refers to

Accepted Answer

A)  a means of communication. 
B)  a man-made object in orbit of Earth. 
C)  the Moon. 
D)  any low-mass object that is orbiting a more massive object. 
E)  none of the above 
A)  a means of communication. 
B)  a man-made object in orbit of Earth. 
C)  the Moon. 
D)  any low-mass object that is orbiting a more massive object. 
E)  none of the above

Question 19

The distance between Earth and the Moon

Accepted Answer

A)  will never change. 
B)  is slowly decreasing. 
C)  is slowly increasing. 
D)  will increase or decrease depending on future changes in the tides on the Moon due to Earth. 
E)  will increase or decrease depending on future changes in the tides on Earth due to the Moon. 
A)  will never change. 
B)  is slowly decreasing. 
C)  is slowly increasing. 
D)  will increase or decrease depending on future changes in the tides on the Moon due to Earth. 
E)  will increase or decrease depending on future changes in the tides on Earth due to the Moon.

Question 20

The force of gravity between Saturn and the Sun is ________ the force of gravity between Earth and the Sun.For reference, Saturn is approximately 100 times more massive than Earth, and the semimajor axis of Saturn's orbit is 10 AU.

Accepted Answer

A)  10 times smaller than 
B)  1,000 times larger than 
C)  1,000 times smaller than 
D)  100 times larger than 
E)  approximately equal to 
A)  10 times smaller than 
B)  1,000 times larger than 
C)  1,000 times smaller than 
D)  100 times larger than 
E)  approximately equal to

Exam 4: Gravity and Orbits

If Earth did not have a moon, would we still have tides because of the Sun? If so, explain how they might be different, or why they might remain unchanged.

Earth is held together in the shape of a sphere.This is due to

Two rocks (call them S and T) are released at the same time from the same height and start from rest.Rock S has 20 times the mass of rock T.Which rock will fall faster if the only forces involved are each rock's mutual gravitational attraction with Earth?

Suppose you are suddenly transported to a planet that had 1/4 the radius of Earth but the same mass as Earth.Your weight would ________ by a factor of ________.

Which of the following is an unbound orbit?

What is the escape velocity from Mars if its mass is 6 *1023 kg and its radius is 3,400 km?

Why are there high and low tides each day instead of having the same tide all day during a given phase of the Moon?

If you doubled the distance the Moon is from Earth, by what fraction does the strength of the tidal force change?

Earth's rotation rate is slowing because of

According to the figure below, when the Moon is in between Earth and the Sun, ________ tides occur.

Which of the following is true considering Newton's laws of motion and Newton's law of gravitation?

Astronauts orbiting Earth in the space shuttle experience so-called weightlessness in space because

Explain why the Moon rotates in the same amount of time as it takes to orbit once around Earth.

If an object is in orbit with an orbital speed less than the escape speed but greater than the circular orbit speed, what type of orbit is it?

Mars has about one-tenth the mass of Earth and half Earth's radius.By what numerical factor does the acceleration of gravity on Mars compare to that on Earth?

What is the escape velocity from Ceres if its mass is 9 * 1020 kg and its radius is 470 km?

When the Sun and Moon are separated by 90 degrees in the sky, ________ tides occur on Earth when the strength of the tides are ________ than normal.

The definition of the term satellite in astronomy refers to

The distance between Earth and the Moon

The force of gravity between Saturn and the Sun is ________ the force of gravity between Earth and the Sun.For reference, Saturn is approximately 100 times more massive than Earth, and the semimajor axis of Saturn's orbit is 10 AU.

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

Suppose you are suddenly transported to a planet that had 1/4 the radius of Earth but the same mass as Earth.Your weight would by a factor of .

What is the escape velocity from Mars if its mass is 6 *10²³ kg and its radius is 3,400 km?

What is the escape velocity from Ceres if its mass is 9 * 10²⁰ kg and its radius is 470 km?

When the Sun and Moon are separated by 90 degrees in the sky, tides occur on Earth when the strength of the tides are than normal.