WebAssign is not supported for this browser version. Some features or content might not work. System requirements

WebAssign

Welcome, demo@demo

(sign out)

Monday, March 31, 2025 12:28 EDT

Home My Assignments Grades Communication Calendar My eBooks

Seeds - Stars and Galaxies - 10/e (Homework)

James Finch

Astronomy, section 1, Fall 2019

Instructor: Dr. Friendly

Current Score : 20 / 45

Due : Monday, January 28, 2030 00:00 EST

Last Saved : n/a Saving...  ()

Print Assignment
Question
Points
1 2 3 4 5 6 7 8 9
1/1 2/7 0/2 15/15 –/8 0/1 1/4 1/1 –/6
Total
20/45 (44.4%)

  • Instructions

    In this Sample Assignment, you will see several of the question types found in Stars and Galaxies, 10th edition, by Michael A. Seeds and Dana Backman and published by Cengage.

    Many of these question types provide scaffolding to build skills and confidence in the use of simple algebra, geometry, and proportional reasoning to solve astronomy problems. Many provide targeted feedback to address specific student errors. Finally, the Virtual Astronomy Laboratories (VALs) provide rich interaction elementsand a sample appears at the end of this sample assignment. This demo assignment allows many submissions and allows you to try another version of the same question for practice wherever the problem has randomized values.

    The answer key and solutions will display after the first submission for demonstration purposes. Instructors can configure these to display after the due date or after a specified number of submissions.

Assignment Submission

For this assignment, you submit answers by question parts. The number of submissions remaining for each question part only changes if you submit or change the answer.

Assignment Scoring

Your last submission is used for your score.

1. 1/1 points  |  Previous Answers SeedsStarsGalaxies10 2.TMP.QL.002. My Notes
Question Part
Points
Submissions Used
1
1/1
1/100
Total
1/1
 
[Quick Lesson Videos were created and narrated by author, Mike Seeds, and provide a unique opportunity to receive instruction from the author himself, which ensures that the voice of the narrative flows from text to digital media.]
Consider the following video.
Which of the following features has the biggest effect on the Earth's seasonal variations?
     Correct: Your answer is correct.
Correct. The tilt of the Earth's axis means more or less direct illumination by the Sun and longer or shorter "daytime" at different times of the year.
Your work in question(s) will also be submitted or saved.
Viewing Saved Work Revert to Last Response
2. 2/7 points  |  Previous Answers SeedsStarsGalaxies10 4.TMP.AT.001. My Notes
Question Part
Points
Submissions Used
1 2 3 4 5 6 7
1/1 –/1 1/1 –/1 0/1 –/1 –/1
1/100 0/100 1/100 0/100 1/100 0/100 0/100
Total
2/7
 
[This is an Animation Tutorial. Animation Tutorials present rich concepts through the use of animations, interactive figures, or other multimedia elements, then assess student learning with a variety of problem types.]
  • Kepler's three laws of orbital motion are fundamental principles. The first two are illustrated in this animation because they both relate to motion around an elliptical orbit. Note that a circle is an ellipse of zero eccentricity, so technically a circular orbit is elliptical. Nevertheless, when most people refer to an elliptical orbit, they mean a noncircular orbit, which is what this animation shows.
    Kepler's first law is really simple. He said that the planets orbit the sun in ellipses with the sun at one focus. The other focus is empty. You can see in the animation how the distance from one focus out to the ellipse and back to the other focus equals a constant. That's why it is so easy to draw an ellipse with two tacks at the two foci (plural of focus) and a loop of string.
    Although Kepler talked about planets orbiting the sun, his first law applies to any object following a closed orbit — that is, any object in an orbit that brings it back to its starting point. In contrast, an open orbit is also governed by gravity but it leads away never to return. Kepler's laws do not apply to open orbits.
    Kepler's second law is more sophisticated. A planet moves around the sun such that a line from the planet to the sun sweeps out equal areas in equal intervals of time. That means the planet moves faster when it is closer to the sun and slower when it is farther away, and you can see that in the animation.
    You can understand why that happens by imagining you are in your spacesuit following in an elongated elliptical orbit around the sun. After you pass the farthest point in your orbit, you begin to move closer to the sun, and the sun's gravity pulls on you and speeds you up. You are actually falling toward the sun, but you miss the sun and whip around it. As you begin to move away from the sun, the sun's gravity pulls back on you and slows you down. So you move faster when you are closer to the sun and slower when you are farther away. By a coincidence of geometry, your speed is proportional to the area being swept out.
    The orbits of the planets are very nearly circular, so Kepler had to be very precise in his calculations to notice that the orbits were elliptical. Also, the variation in speed for the planets is not very great, so again, it wasn't obvious. Also remember that nearly all astronomers at the time believed in uniform circular motion, so it took a great deal of insight and courage for Kepler to say, no, the orbits are not circles and the planets do not move uniformly.
  • Which of the following describes a planet following an elliptical orbit around the sun?
        
  • Which of the following describes the distance from a focus to the planet and back to the other focus?
        
  • When does the planet move at its fastest speed?
        
  • Kepler's first two laws of planetary motion can only be applied to which of the following?
        
  • Kepler's first two laws apply to which of the following?
        
  • Why is Kepler's discovery of his first two laws of planetary motion impressive?
        
  • In this tutorial, you learned how Kepler's first two laws describe the orbital motion of the planets orbiting the sun. Which of the following is true?
        
Your work in question(s) will also be submitted or saved.
Viewing Saved Work Revert to Last Response
3. 0/2 points  |  Previous Answers SeedsStarsGalaxies10 2.SP.OP.013. My Notes
Question Part
Points
Submissions Used
1 2
0/1 0/1
1/100 1/100
Total
0/2
 
[This is an Optimized Problem. Optimized Problems offer randomized parameters and provide immediate feedback to students who have incorrectly answered any part of the problem. Try putting in an incorrect answer to see an example of this just-in-time assistance.]
If you are at latitude 70 degrees north of Earth's equator, what is the angular distance (in degrees) from your zenith to the north celestial pole?
Incorrect: Your answer is incorrect. seenKey

20
How is the angular distance to the north celestial pole related to your latitude? How does that relate to the point directly overhead? Refer to the diagrams of the celestial sphere in the textbook.°
What is the shortest angular distance (in degrees) from your nadir to the north celestial pole?
Incorrect: Your answer is incorrect. seenKey

160
How is the angular distance to the north celestial pole related to your latitude? How does that relate to the point directly below your feet? Refer to the diagrams of the celestial sphere in the textbook °
Your work in question(s) will also be submitted or saved.
Viewing Saved Work Revert to Last Response
4. 15/15 points  |  Previous Answers SeedsStarsGalaxies10 9.SP.RTE.0001a. My Notes
Question Part
Points
Submissions Used
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1 1/1
1/100 1/100 1/100 1/100 1/100 1/100 1/100 1/100 1/100 1/100 1/100 1/100 1/100 1/100 1/100
Total
15/15
 
[This is a Sense-of-Proportion question. These are brief ranking/analytical questions that help students comprehend the breadth of different proportionalities that exists within Astronomy.]
Answer the questions below.
An H-R diagram is shown with the names of specific stars plotted. This diagram has 4 axis labels, one on each side of the plot.
  • The bottom horizontal axis is labeled Temperature (K) and it begins at 40,000 K on the left to 1000 K on the right.
  • The top horizontal axis is labeled "Spectral type" and is sectioned at certain intervals. The region between 40,000 kelvin and around 30,000 kelvin is labeled O. The region between 30,000 kelvin and 10,000 kelvin is labeled B. The region between 10,000 kelvin and 8000 kelvin is labeled A. The region between 8000 kelvin and 6000 kelvin is labeled F. The region between 6000 kelvin and 4500 kelvin is labeled G. The region between 4500 kelvin and 3500 kelvin is labeled K. The region between 3500 kelvin and 1000 kelvin is labeled M.
  • The vertical axis on the left is labeled Luminosity in L/LSun. It ranges from 10−5 at the bottom and ends at 106 at the top.
  • The vertical axis on the right is labeled Absolute Magnitude in MV and it ranges from 15 at the bottom to -10 at the top.
  • The Main sequence of the stars enters the viewing window from the left at 105.5 L/LSun and moves down and to the right at a constant slope until it approaches 3300 K, where it takes a sharp drop until it exits the viewing window. The Red dwarfs occupy the bottom of the Main sequence. Supergiants occupy a broad region at Luminosities above 104 L/LSun in the upper left and upper right regions of the diagram above the Main sequence. The Giants occupy a broad region to the right of and above the Main sequence but lower than the supergiants. The white dwarfs occupy a broad region below the Main sequence.
  • Parallel, diagonal dashed lines are present on the diagram to indicate the radii of the stars. The 0.01 RSun line cuts across the region of white dwarfs. The 0.1 RSun line cuts across the region of red dwarfs. The 1 RSun line runs through the lower part of the Main sequence. The Sun is on this line. The 10 RSun line cuts across the very top of the Main sequence and through the lower left region of Giants. The 100 RSun line cuts through the central region of Supergiants and the top right region of Giants. The 1000 RSun line cuts through the right region of Supergiants.
(a) Rank the following stars from the above H-R diagram in order of brightness from dimmest to brightest: Barnard's Star, Canopus, Rigel A, Sirius B, Sun.
dimmest Correct: Your answer is correct. seenKey

Barnard's Star
Correct: Your answer is correct. seenKey

Sirius B
Correct: Your answer is correct. seenKey

Sun
Correct: Your answer is correct. seenKey

Canopus
brightest Correct: Your answer is correct. seenKey

Rigel A
(b) Rank the following stars from the above H-R diagram in order of brightness from brightest to dimmest: Aldebaran A, Altair, Antares, Polaris, Procyon B.
brightest Correct: Your answer is correct. seenKey

Antares
Correct: Your answer is correct. seenKey

Polaris
Correct: Your answer is correct. seenKey

Aldebaran A
Correct: Your answer is correct. seenKey

Altair
dimmest Correct: Your answer is correct. seenKey

Procyon B
(c) Rank the following stars from the above H-R diagram in order of temperature from hottest to coolest: Aldebaran A, Altair, Antares, Mira, Rigel A.
hottest Correct: Your answer is correct. seenKey

Rigel A
Correct: Your answer is correct. seenKey

Altair
Correct: Your answer is correct. seenKey

Aldebaran A
Correct: Your answer is correct. seenKey

Mira
coolest Correct: Your answer is correct. seenKey

Antares
Your work in question(s) will also be submitted or saved.
Viewing Saved Work Revert to Last Response
5. –/8 points SeedsStarsGalaxies10 9.PFB.P.005. My Notes
Question Part
Points
Submissions Used
1 2 3 4 5 6 7 8
–/1 –/1 –/1 –/1 –/1 –/1 –/1 –/1
0/100 0/100 0/100 0/100 0/100 0/100 0/100 0/100
Total
–/8
 
[This is a end-of-chapter Problem from the textbook. Numbers and contextual details may be randomized (represented by red text) for a customized learning experience and to assist when studying for an exam. Click 'Practice Another Version' to receive a newly-randomized question to practice.]
Complete the following table.
mV (mag) MV (mag) d (pc) p (arc seconds)
3 10
17 100
−8
 		0.025
5 0.022
Your work in question(s) will also be submitted or saved.
Viewing Saved Work Revert to Last Response
6. 0/1 points  |  Previous Answers SeedsStarsGalaxies10 9.SP.GP.004. My Notes
Question Part
Points
Submissions Used
1
0/1
1/100
Total
0/1
 
[This is a General Problem. General Problems are multiple-select items, in which several choices may be correct. They invite students to synthesize descriptive knowledge about a particular topic.]

Based on what you know about the masses of stars, select all of the correct statements from the following list.
Incorrect: Your answer is incorrect.

Your work in question(s) will also be submitted or saved.
Viewing Saved Work Revert to Last Response
7. 1/4 points  |  Previous Answers SeedsStarsGalaxies10 4.TMP.Tut.001. My Notes
Question Part
Points
Submissions Used
1 2 3 4
1/1 –/1 –/1 –/1
1/100 0/100 0/100 0/100
Total
1/4
 
[This is a Tutorial. Tutorials coach the student through every step of the most essential astronomical problems. These highly structured, scaffolded learning activities give strong support to the student with emerging or dormant quantitative-reasoning skills.]
Tutorial
The orbital period of Saturn is 29.5 times that of Earth. How much farther from the Sun is Saturn than Earth?
Part 1 of 3
Kepler's Third Law describes how the distance of a planet from the Sun and its orbital period are related,
P2 = a3,
where the period is expressed in Earth years and the distance is expressed in AU.
Part 2 of 3
If a planet has an orbital period that is larger than another planet, is the planet with the larger orbital period farther away or closer to the Sun?
     Correct: Your answer is correct.
Part 3 of 3
We want to compare the orbital properties of Saturn and Earth. We know that Saturn has an orbital period that is 29.5 times longer than that of Earth. Using Kepler's Third Law, we have two expression for Saturn and Earth.
(PSaturn)2 = (aSaturn)3
(PEarth)2 = (aEarth)3
We can write our expression for
PSaturn
 as
(PSaturn)2 = 
 PEarth
2
 
,
and substitute in for the distances.
(aSaturn)3 =  (aEarth)3
aSaturn =  aEarth


Your work in question(s) will also be submitted or saved.
Viewing Saved Work Revert to Last Response
8. 1/1 points  |  Previous Answers SeedsStarsGalaxies10 3.PFB.RQ.003. My Notes
Question Part
Points
Submissions Used
1
1/1
1/100
Total
1/1
 
[This is a Review Question. Generally adapted from the textbook, Review Questions provide opportunities for test prep and formative assessment.]
You are located in New York, NY, 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?
     Correct: Your answer is correct.
Your work in question(s) will also be submitted or saved.
Viewing Saved Work Revert to Last Response
9. –/6 points SeedsStarsGalaxies10 VAL.4.002. My Notes
Question Part
Points
Submissions Used
1 2 3 4 5 6
–/1 –/1 –/1 –/1 –/1 –/1
0/100 0/100 0/100 0/100 0/100 0/100
Total
–/6
 
[Each Virtual Astronomy Laboratory (VAL) is presented in a modular format, containing individual auto-graded segments that can be combined in different ways to create a more-tailored pedagogical experience. Many items provide scaffolding to build skills and confidence in the use of simple algebra, geometry, and proportional reasoning to solve astronomy problems.]

The Earth's Magnetic Field

The photo below shows an auroral display seen from Landmannarlaugar, Iceland. Many aurora-seekers travel to Iceland because the island nation is so close to the Earth's north magnetic pole. Magnetic-field lines converge there, concentrating the flow of charged particles and boosting the odds of seeing the Northern Lights.
But that's not the only benefit of Earth having a strong, well-ordered magnetic field. Because magnetic fields exert forces upon moving charges, we on Earth are largely shielded from the solar wind—especially intense during solar storms—and from rare but high-powered cosmic rays: atomic nuclei hurtling across space from sources such as supernova explosions and black holes. This shielding greatly reduces the risks of radiation damage and mutation in terrestrial life forms.
In this section we'll learn about the forces that allow magnetic fields to shape the aurorae while shielding the Earth from hazardous particles.
A photograph of an auroral display seen from Landmannarlaugar, Iceland.
  • The Earth's magnetic field exerts forces on moving charged particles, and this shields nearly all of the Earth's surface from the solar wind and from cosmic rays.
    The Earth has a powerful magnetic field because currents of iron-nickel alloy are circulating in its liquid core. When the electrically charged particles of the solar wind encounter the Earth's magnetic field, they experience a force called the Lorentz force.
    In a nutshell, charged particles in a magnetic field experience a force that is perpendicular to both the direction of the field and the direction of the particles' motion.
    The strength of the force depends on the amount of electric charge, how fast the charges are moving, and the strength of the magnetic field. Particles that have no charge do not experience this force. Nor do particles that are stationary, regardless of whether or not they are charged.
    The following activity allows us to explore the nature of this unusual but essential force—a force that operates in toys, cars, power tools, and anything else with an electric motor.
    An illustration of the magnetic field of the Earth. Field lines emanate from the south magnetic pole and converge at the north magnetic pole.
    This conceptual illustration shows selected magnetic-field lines emanating from one magnetic pole and converging on the other. This dipole field pattern is similar to that of a simple bar magnet.

  • Magnetic Forces

    The Magnetic Forces simulation allows us to explore the effects that magnetic fields have on moving charged particles. Note that you can change the direction of the magnetic field and the type of particles entering the magnetized region, both by using radio buttons near the bottom of the frame. in addition, sliders allow you to modify the magnetic field strength and the particle energy (related to speed). Note that you can adjust the sliders by using your keyboard's left and right arrow keys, but first you must click on the dot at the end of the slider you wish to manipulate.
    Take a minute to familiarize yourself with the functions of the simulation. Then conduct the exercises that appear below.
    Use the Magnetic Force simulation to complete the table below. For Particle Deflection Direction, indicate whether the particles move left, right, or neither (undeflected). Feel free to adjust the magnetic field strength or particle energy to make the effects easier to study. (For example, electrons feel magnetic forces much more strongly than do protons, since they have equal amounts of charge—sign aside—but very different masses.)
    Particle Type Magnetic Field
    Direction     		Particle Deflection
    Direction
    Protons Into Screen
    Out of Screen
    Electrons Into Screen
    Out of Screen
    Neutrons Into Screen
    Out of Screen
Your work in question(s) will also be submitted or saved.
Viewing Saved Work Revert to Last Response
Home My Assignments
Enter a number.
Enter a number.
Enter a number.
Enter a number.
Enter a number.
Enter a number.
Enter a number.
Enter a number.
Enter a number.
Enter a number.
Enter a number.
Enter a number.
Enter a number.