Question 1

According to the scales in the figure, about how many times stronger is gravity on Earth than on the Moon?

Accepted Answer

A)  20 
B)  3 
C)  2 
D)  6 
E)  They are the same. 
A)  20 
B)  3 
C)  2 
D)  6 
E)  They are the same.

Question 2

Figure 1
-According to Figure 1, the approximate amount of time between two high tides at a given location is:

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 3

You discover a moon orbiting a planet. The moon has an orbital period of three weeks, and the average distance between the moon and planet is 1.2 * 106 km. What is the planet's mass? Compare its mass to that of Jupiter, which is 1.9 * 1027 kg.

Accepted Answer

Use the equation M =4 @#LAT-DLM&²A

Question 4

Astronauts orbiting Earth in the space shuttle feel weightless in space because:

Accepted Answer

A)  they are farther away from the Earth 
B)  they eat less food while in orbit 
C)  the gravitational pull of the Moon counteracts the Earth's gravitational pull 
D)  they are in constant free fall around the Earth 
E)  they are in space where there is no gravity 
A)  they are farther away from the Earth 
B)  they eat less food while in orbit 
C)  the gravitational pull of the Moon counteracts the Earth's gravitational pull 
D)  they are in constant free fall around the Earth 
E)  they are in space where there is no gravity

Question 5

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

Accepted Answer

The Moon's tidal locking is ca

Question 6

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

Accepted Answer

A)  increase; 4 
B)  increase; 16 
C)  decrease; 4 
D)  decrease; 16 
E)  increase; 2 
A)  increase; 4 
B)  increase; 16 
C)  decrease; 4 
D)  decrease; 16 
E)  increase; 2

Question 7

Mass and weight are different names for the same physical property of matter.

Accepted Answer

A) True 
 B)False

Question 8

All objects on Earth, regardless of the size of their mass, fall with the same acceleration.

Accepted Answer

A) True 
 B)False

Question 9

How does the force of gravity between the Sun and Mercury compare to the gravitational force between the Sun and the Earth? Note that the semimajor axis of Mercury's orbit is 0.4 AU, and Mercury's mass is 0.06 times the mass of the Earth.

Accepted Answer

For a planet, the force of gravity betwe

Question 10

You find a moon orbiting a planet. The moon has a period of 10 days, and the average distance between the moon and planet is 106 km. What is the planet's mass? Note that the mass of Jupiter is 1.9 * 1027 kg.

Accepted Answer

A)  0.1 MJupiter 
B)  0.4 MJupiter 
C)  1 MJupiter 
D)  4 MJupiter 
E)  10 MJupiter 
A)  0.1 MJupiter 
B)  0.4 MJupiter 
C)  1 MJupiter 
D)  4 MJupiter 
E)  10 MJupiter

Question 11

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 the Earth 
E)  will increase or decrease depending on future changes in the tides on the 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 the Earth 
E)  will increase or decrease depending on future changes in the tides on the Earth due to the Moon

Question 12

Consider the figure below that illustrates the tidal bulge on the Earth's oceans due to the Moon and four people at different longitudes on the Earth from the point of view of an observer looking down on the North Pole of the Earth. If you were to arrive at the beach and find that the Moon was visible in the western half of the sky, then is the tide most likely to be coming in and the water level rising; or is the tide going out and the water level going down? Explain the rationale for your answer.

Accepted Answer

If the Moon is in the western half of th

Question 13

Saturn has 95 times the mass of Earth, and its atmosphere extends outward 9.5 times the Earth's radius. How does the acceleration due to gravity at the edge of Saturn's atmosphere compare to that on the Earth?

Accepted Answer

g = GM/R²; thus g_S

Question 14

The Hubble Space Telescope orbits at an altitude of 600 km above the Earth's surface. Assuming it is in a stable circular orbit, what is its velocity? For reference, the 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 15

More massive objects fall faster in the Earth's gravitational field than less massive objects.

Accepted Answer

A) True 
 B)False

Question 16

The Earth's rotation rate is slowing because of:

Accepted Answer

A)  radioactive decays 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 decays 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 17

In a system with three gravitating bodies, there are _________ stable locations called _________ points for the third object to orbit in lockstep with the two more massive objects.

Accepted Answer

A)  3; tidal 
B)  2; tidal 
C)  4; Roche 
D)  2; Lagrange 
E)  5; Lagrange 
A)  3; tidal 
B)  2; tidal 
C)  4; Roche 
D)  2; Lagrange 
E)  5; Lagrange

Question 18

Show that the tidal force on Earth from the Moon is approximately two times the tidal force on Earth from the Sun. For reference, Moon's mass is 7.3 *1022 kg, the Sun's mass is 2 * 1030 kg, the Earth-Moon distance is 3.8 * 105 km, and the Earth-Sun distance is 1.5*108 km.

Accepted Answer

The tidal force on the Earth due to a bo

Question 19

If you weighed 100 lbs on Earth, what would you weigh at the upper atmosphere of Jupiter? For reference, Jupiter has a mass that is about 300 times the Earth's mass and a radius that is 10 times the Earth's radius.

Accepted Answer

A)  10,000 lbs 
B)  3,000 lbs 
C)  1,000 lbs 
D)  300 lbs 
E)  30 lbs 
A)  10,000 lbs 
B)  3,000 lbs 
C)  1,000 lbs 
D)  300 lbs 
E)  30 lbs

Question 20

Mercury orbits the Sun with an average distance of 0.4 AU, and its mass is 0.06 times that of the Earth. The gravitational force that the Sun exerts on Mercury is _______________ times the force of gravity that the Sun exerts on the Earth.

Accepted Answer

A)  20 
B)  6 
C)  4 
D)  0.4 
E)  0.1 
A)  20 
B)  6 
C)  4 
D)  0.4 
E)  0.1

Exam 4: Gravity and Orbits

According to the scales in the figure, about how many times stronger is gravity on Earth than on the Moon?

Figure 1 -According to Figure 1, the approximate amount of time between two high tides at a given location is:

You discover a moon orbiting a planet. The moon has an orbital period of three weeks, and the average distance between the moon and planet is 1.2 * 106 km. What is the planet's mass? Compare its mass to that of Jupiter, which is 1.9 * 1027 kg.

Astronauts orbiting Earth in the space shuttle feel weightless in space because:

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

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

Mass and weight are different names for the same physical property of matter.

All objects on Earth, regardless of the size of their mass, fall with the same acceleration.

How does the force of gravity between the Sun and Mercury compare to the gravitational force between the Sun and the Earth? Note that the semimajor axis of Mercury's orbit is 0.4 AU, and Mercury's mass is 0.06 times the mass of the Earth.

You find a moon orbiting a planet. The moon has a period of 10 days, and the average distance between the moon and planet is 106 km. What is the planet's mass? Note that the mass of Jupiter is 1.9 * 1027 kg.

The distance between Earth and the Moon:

Saturn has 95 times the mass of Earth, and its atmosphere extends outward 9.5 times the Earth's radius. How does the acceleration due to gravity at the edge of Saturn's atmosphere compare to that on the Earth?

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

More massive objects fall faster in the Earth's gravitational field than less massive objects.

The Earth's rotation rate is slowing because of:

In a system with three gravitating bodies, there are _________ stable locations called _________ points for the third object to orbit in lockstep with the two more massive objects.

Show that the tidal force on Earth from the Moon is approximately two times the tidal force on Earth from the Sun. For reference, Moon's mass is 7.3 *1022 kg, the Sun's mass is 2 * 1030 kg, the Earth-Moon distance is 3.8 * 105 km, and the Earth-Sun distance is 1.5*108 km.

If you weighed 100 lbs on Earth, what would you weigh at the upper atmosphere of Jupiter? For reference, Jupiter has a mass that is about 300 times the Earth's mass and a radius that is 10 times the Earth's radius.

Mercury orbits the Sun with an average distance of 0.4 AU, and its mass is 0.06 times that of the Earth. The gravitational force that the Sun exerts on Mercury is _______________ times the force of gravity that the Sun exerts on the Earth.

Why Learn Astronomy

Patterns in the Skymotions of Earth

Motion of Astronomical Bodies

Light

The Tools of the Astronomer

The Birth and Evolution of Planetary Systems

The Terrestrial Planets and Earths Moon

Atmospheres of the Terrestrial Planets

Worlds of Gas and Liquid the Giant Planets

Planetary Adornmentsmoons and Rings

Dwarf Planets and Small Solar System Bodies

Taking the Measure of Stars

Our Starthe Sun

Star Formation and the Interstellar Medium

Evolution of Low-Mass Stars

Evolution of High-Mass Stars

Relativity and Black Holes

The Expanding Universe

Galaxies

The Milky Waya Normal Spiral Galaxy

Modern Cosmology

Large-Scale Structure in the Universe

Life

Filters

You discover a moon orbiting a planet. The moon has an orbital period of three weeks, and the average distance between the moon and planet is 1.2 * 10⁶ km. What is the planet's mass? Compare its mass to that of Jupiter, which is 1.9 * 10²⁷ kg.

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

You find a moon orbiting a planet. The moon has a period of 10 days, and the average distance between the moon and planet is 10⁶ km. What is the planet's mass? Note that the mass of Jupiter is 1.9 * 10²⁷ kg.

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

In a system with three gravitating bodies, there are _ stable locations called _ points for the third object to orbit in lockstep with the two more massive objects.

Show that the tidal force on Earth from the Moon is approximately two times the tidal force on Earth from the Sun. For reference, Moon's mass is 7.3 10²² kg, the Sun's mass is 2 10³⁰ kg, the Earth-Moon distance is 3.8 * 10⁵ km, and the Earth-Sun distance is 1.5*10⁸ km.