WebAssign Homeworks
Rank the lunar phases shown in the order that they appear during a month: waxing crescent, first quarter, waxing gibbous, full moon.
(1st phase) Waxing Crescent → First Quarter → Waxing Gibbous → Full Moon (Last Phase)
Rank the lunar phases in the order of the time of day the moon will rise in each phase: waxing crescent, first quarter, waxing gibbous, full moon.
(Earliest) Waxing Crescent → First Quarter → Waxing Gibbous → Full Moon (Latest)
Rank the lunar phases in the order of the amount of time at night you will see the moon in each phase: waxing crescent, first quarter, waxing gibbous, full moon.
(Longest) Full Moon → Waxing Gibbous → First Quarter → Waxing Crescent
If you looked back at Earth from the Moon, what phase would Earth have when the Moon is in the following phases?
*The phases are opposite Full → New New → Full First Quarter → Third Quarter Waxing Crescent → Waning Gibbous
What is the difference between the Solar System, the Galaxy, and the Universe? (Select all that apply.)
- The Solar System contains the sun and objects that orbit it, including the eight planets, comets, and asteroids, and the Galaxy contains approximately 100 billion stars, of which the sun is one, as well as large clouds of gas and dust. - The universe contains all physical matter and energy. Its basic constituents are the clusters of galaxies.
Based on what you know about falling objects, select all of the correct statements from the following list. (Ignore the effects of air resistance.)
- The speed of the falling objects increases at a constant rate. - According to tradition, Galileo dropped objects of different mass from the leaning tower of Pisa. - The acceleration due to gravity near Earth's surface is 9.8 m/s² - Inertia is an object's tendency to resist changes in its motion
Use the small-angle formula to calculate the angular diameter of Jupiter (in degrees) as seen from its moon Europa. (Note: The linear diameter of Jupiter is 1.43 ✕ 1065 km, and the distance from Jupiter to Europa is 6.71 ✕ 10^5 km.)
12.165°
Compared to the strength of Earth's gravity at its surface r=RE where RE is the radius of the Earth, how much weaker is gravity at a distance of r=14 RE? How much weaker is gravity at a distance of r-20 RE?
196 times 400 times
Light from the Sun takes 8 minutes to reach Earth. How long (in min) does it take to reach Neptune, 30.1 AU from the Sun?
240.8 min
Where is the center of mass of the Earth-Moon system?
4,670 km from the center of Earth in the line from the center of Earth to the center of the Moon.
If the semimajor axis of a planet is 4 AU, what is its orbital period?
8 years
Light from the Sun takes 8 minutes to reach Earth. How long (in min) does it take to reach Neptune, 30.1 AU from the Sun?
80,000 years
Saturn orbits the Sun with a period of 29.46 years. What is its average distance (in AU) from the Sun? (Round your answer to at least four significant figures.)
9.5387 AU
What does Kepler's second law indicate about the orbital speed of a planet?
A planet moves at its farthest when it is closest to the Sun.
How far must a spacecraft go to be "beyond Earth's gravity"? Why?
Actually, a spacecraft can never be completely out of Earth's gravity. All objects exert at least a small amount of gravity on all other objects, no matter how far they are from each other.
Who first proposed that gravity is the bending of space-time due to the presence of matter?
Albert Eistein (1879-1955)
Where in an elliptical orbit will a planet have the fastest orbital speed?
At the point closest to the Sun.
The changes in the previous two questions are examples of which of the following?
Conservation of angular momentum.
What id the phase of Venus when it is closest? What is the phase of Venus when it is farthest? How do you know?
Crescent Near full When Venus is closest to Earth it will be *between the Sun and Earth, showing mostly the side that *is not* illuminated by the Sun. When it is farthest away it will be *on the opposite side of the Sun from Earth*, showing mostly the side that *is* illuminated by the Sun.
What are two reasons why winter days are colder than summer days?
During the winter, light from the sun hits Earth at a more oblique angle than it does during the summer. The length of time that the sun is above the horizon is noticeably shorter during the winter than during the summer.
Rank the following distances in order from smallest to largest: sun to nearest star, Earth to sun, Earth to moon, Milky Way Galaxy to next nearest galaxy.
Earth to moon ← Earth to sun ← sun to nearest star ← Milky Way Galaxy to next nearest galaxy
Use what you learned in Chapter 1 to rank the following objects from smallest to largest: Earth, Milky Way Galaxy, solar system, sun.
Earth ← Sun ← Solar System ← Milky Way Galaxy
Describe the shape of the orbit followed by the cannonball in the figure below pretending that the cannonball could pass freely through Earth.
Ellipse with lower focus at Earth's center.
Rank the following objects from largest to smallest: filament, galaxy, planet, star.
Filament → Galaxy → Star → Planet
Why is the "line of tidal bulges" on Earth slightly ahead of the moon in its orbit as shown in this figure?
Friction with ocean beds drags the bulges ahead as Earth rotates.
Rank the following objects from brightest to dimmest: Polaris, full moon, Sirius, Venus.
Full Moon → Venus → Sirius→ Polaris
Rank the phases of the Moon from brightest to dimmest in order of decreasing brightness.
Full Moon → Waning Gibbous → Third Quarter → Waning Crescent → New Moon
A satellite is in orbit at a distance r from the center of the Earth. If the orbit radius is reduced to 1/3 of its original radius so that the satellite is orbiting closer to the Earth's surface, will the field strength increase, decrease, or stay the same? If it changes, by how much?
Increase Final strength/initial strength = 9
What is true about the solar corona?
It is the outermost layer of the sun.
North is up in this figure. Can we tell whether the daylight and darkness line at the right is the sunset line or the sunrise line?
It is the sunset line because Earth rotates counterclockwise when viewed from above Earth's North Pole. *More land is being moved in the darkness as time passes.
What does the word apparent mean in apparent visual magnitude?
It means that the magnitude describes how bright the star appears to us, observing from Earth.
How does Kepler's 1st law of planetary motion overthrow one of the basic beliefs of classical astronomy?
Kepler's 1st law says that the orbits of the planets are ellipses, rather than perfect circles or series of epicycles.
How does Kepler's 2nd law of planetary motion overthrow one of the basic beliefs of classical astronomy?
Kepler's 2md law says that planets speed up and slow down during their orbits rather than remain in uniform motion.
How does Kepler's first law of planetary motion overthrow one of the basic beliefs of classical astronomy?
Kepler's first law says that the orbits of the planets are ellipses, rather than perfect circles or series of epicycles.
How about Kepler's second law?
Kepler's second law says that the planets speed up and slow down during their orbits, rather than remain in uniform motion.
Which is an unchanging measurement of the amount of matter an object is made of?
Mass
Rank the magnitude differences between the following pairs of objects (or magnitudes) from the biggest difference to the smallest difference: Sun/full moon, Venus/Sirius, Venus/Polaris, naked eye limit/Hubble space telescope limit.
Naked eye limit/Hubble space telescope limit → Sun/Full Moon → Venus/Polaris → Venus/Sirius
Rank the phases of the Moon from dimmest to brightest in order of increasing brightness.
New moon ← Waxing Crescent ← First Quarter ← Waxing Gibbous ← Full Moon
If you drop a feather and steel hammer at the same moment, they should hit the ground at the same instant. Why doesn't this work on Earth, and why does it work on the moon? Will it work on Phobos, a moon of Mars? (Consider that Phobos is a very small, low-density, rocky moon with no atmosphere)
On Earth, air resistance slows the feather, which falls at nearly constant speed, while the hammer accelerates downward, constantly increasing its speed. On the Moon, there is no atmosphere so the motion of the feather is not impeded by air resistance, and both the feather and hammer continue to accelerate as they fall. Yes
The stamp below shows the constellation Orion. Explain why this looks odd to residents of the Northern Hemisphere.
Orion appears upside down compared to how it looks in the Northern Hemisphere.
Rank the following objects in the figure from dimmest to brightest: Sun, Polaris, Venus, Sirius.
Polaris ← Sirius ← Venus ← Sun
What happens if a spinning ice-skater brings her arms in closer to her body?
She will spin faster/
Why do solar eclipses happen only at new moon? Why not every new moon?
Since the shadow of the Moon extends directly away from the Sun, a solar eclipse can occur only when the Moon is between the Earth and the Sun. Solar eclipses don't occur every new moon because of the Moon's orbital tilt.
Which of the following lists is in order of increasing size?
Solar System ← Milky Way Galaxy ← Universe
If Star B has mB = −1 and Star A ma = −4, from which star does Earth receive more flux?
Star A *Lower magnitude = brighter
According to Newton's laws, how does the amount of gravitational force exerted on Earth by the Sun compare to the amount of gravitational force exerted on the Sun by Earth?
The amount of force exerted on the Sun by Earth is the same as the amount of force exerted on Earth by the Sun.
We can see total solar eclipses because of which of the following?
The angular diameters of the sun and the moon are almost equal.
Which of the following is true for an observer located at the tip of the umbra in this figure?
The angular size of the tack is the same as the angular size of the light source.
What is the center mass of two bodies?
The balance point for the 2 bodies.
How does the date of the beginning of summer in Earth's Southern Hemisphere differ from the date in the Northern Hemisphere?
The dates are six months apart. The summer begins in late June in the Northern Hemisphere and in late December in the Southern Hemisphere.
What is the difference between speed and velocity?
The velocity of an object indicates both the object's speed (rate of motion) and its direction of motion.
If a 1 kg rock and a 6 kg rock were dropped from the same height above the moon's surface at the same time, they would both strike the moon's surface at the same time. The gravitational force with which the moon pulls on the 6 kg rock is 6 times greater than the 1 kg rock. Why then do the two rocks strike the moon's surface at the same time?
They both have the same acceleration because acceleration is the force divided by the mass.
If the moon reaches full phase on May 6, it is at _______ phase on May 17.
Waning Crescent
You are located in Memphis, TN, United States. Your friend is located in Santiago, Chile. You see a waning gibbous in your clear night sky. What phase, if any, will your friend see if the night sky in Santiago is also clear?
Waning Gibbous
Which is the measurement of the force that gravity exerts on an object?
Weight
Which measurement would be different for you on the moon?
Weight
Which statement below best describes the difference between your mass and your weight?
Your mass is a measure of the amount of matter that you contain and your weight is a measure of the amount of gravitational pull that you experience.
Which type of eclipse may be visible to all the people on one side of Earth?
a total lunar eclipse
During which eclipse type will the solar corona be observable?
a total solar eclipse
If Earth had no atmosphere, what color would the eclipsed moon appear in the sky?
dark, essentially invisible
Match the phase of the moon to the time of day when that phase is highest overhead.
midnight = full moon early morning = waning gibbous sunrise = third quarter morning = waning crescent noon = new moon afternoon = waxing crescent sunset = first quarter evening = waxing gibbous
About how many stars are in our home galaxy, also known as the Milky Way Galaxy?
over 100,000,000,000
Rank the ratio of the distances compared to the size of the objects involved in order from largest to smallest: sun to nearest star, Earth to sun, Earth to moon, Milky Way Galaxy to next nearest galaxy.
sun to nearest > Earth to sun > Earth to moon > Milky Way Galaxy to next nearest galaxy
Which of the following descriptions is a definition of an astronomical unit (AU)?
the average distance between Earth and the sun
Visibility of the solar corona is limited by which of the following?
the brightness of the Sun's photosphere