Astronomy
1st Edition
ISBN: 9781938168284
Author: Andrew Fraknoi; David Morrison; Sidney C. Wolff
Publisher: OpenStax
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Textbook Question
Chapter 20, Problem 23E
Thinking about the topics in this chapter, here is an Earth analogy. In big cities, you can see much farther on days without smog. Why?
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PLEASE help me with the two questions. These are the only two I need help with and this is my last question until November. Please solve number #7 from the information in 6, and please solve question #9 from the information in number 8. THANK YOU PLEASE HELP!!
Calculate the angle a person needs to lean from the vertical when
1. walking a 14 m (radius) circular track at 22 mins per mile, and
Enter to 2 significant figures
Angle with respect to the vertical =
= 0.85
! No, that's not the correct answer.
O
2. running at 4 min per mile.
Enter to 2 significant figures
Angle with respect to the vertical = 6.8
Use 1 mile = 1609.4 m
Sense-making: Do your results for the leaning angle during walking agree with your observations
about people walking on circular tracks?
O
1Which of the following best describes a frame of reference?
an experiment that proved that Earth did not have an aether wind
the theory that describes the behavior and characteristics of objects moving at relativistic speeds
the effect of the slowing of time as an object moves with high speeds
a point in which someone relates the behavior of an object from one perspective
2If an electron moves from n = 5 to n = 1, what wavelength of light is emitted? (h = 6.626 x 10-34, 1 eV = 1.6 x 10-19 J)
4008 nm
434 nm
95 nm
1281 nm
3Which of the following best describes a frame of reference?
an experiment that proved that Earth did not have an aether wind
the theory that describes the behavior and characteristics of objects moving at relativistic speeds
the effect of the slowing of time as an object moves with high speeds
a point in which someone relates the behavior of an object from…
Chapter 20 Solutions
Astronomy
Ch. 20 - Identify several dark nebulae in photographs in...Ch. 20 - Why do nebulae near hot stars look red? Why do...Ch. 20 - Describe the characteristics of the various kinds...Ch. 20 - Prepare a table listing the different ways in...Ch. 20 - Describe how the 21-cm line of hydrogen is formed....Ch. 20 - Describe the properties of the dust grains found...Ch. 20 - Why is it difficult to determine where cosmic rays...Ch. 20 - What causes reddening of starlight? Explain how...Ch. 20 - Why do molecules, including H2 and more complex...Ch. 20 - Why can’t we use visible light telescopes to study...
Ch. 20 - The mass of the interstellar medium is determined...Ch. 20 - Where does interstellar dust come from? How does...Ch. 20 - Figure 20.2 shows a reddish glow around the star...Ch. 20 - If the red glow around Antares is indeed produced...Ch. 20 - Even though neutral hydrogen is the most abundant...Ch. 20 - The terms H II and H2 are both pronounced “H two.”...Ch. 20 - Suppose someone told you that she had discovered H...Ch. 20 - Describe the spectrum of each of the following: A....Ch. 20 - According to the text, a star must be hotter than...Ch. 20 - From the comments in the text about which kinds of...Ch. 20 - One way to calculate the size and shape of the...Ch. 20 - New stars form in regions where the density of gas...Ch. 20 - Thinking about the topics in this chapter, here is...Ch. 20 - Stars form in the Milky Way at a rate of about 1...Ch. 20 - The 21-cm line can be used not just to find out...Ch. 20 - Astronomers recently detected light emitted by a...Ch. 20 - We can detect 21-cm emission from other galaxies...Ch. 20 - We have said repeatedly that blue light undergoes...Ch. 20 - Suppose that, instead of being inside the Local...Ch. 20 - Suppose that, instead of being inside the Local...Ch. 20 - A molecular cloud is about 1000 times denser than...Ch. 20 - Would you expect to be able to detect an H II...Ch. 20 - Suppose that you gathered a ball of interstellar...Ch. 20 - At the average density of the interstellar medium,...Ch. 20 - Consider a grain of sand that contains 1 mg of...Ch. 20 - H II regions can exist only if there is a nearby...Ch. 20 - In the text, we said that the five-times ionized...Ch. 20 - Dust was originally discovered because the stars...Ch. 20 - How would the density inside a cold cloud (T=10K)...Ch. 20 - The text says that the Local Fluff, which...
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