1. Use the concept of the barycenter to explain why the Earth and the moon revolve around each other. (Also see fig. 9.1 and p. 518)
2. Explain why the Earth-Moon barycenter is inside Earth, not at the halfway point between Earth and the moon. (Also see fig. 9.1)
3. List the two tide-generating forces.
4. Write the gravitational force equation. (Also see Newton's law of universal force definition on p. 528)
5. Explain how a gravitational force changes at masses increase or decrease, and as distance increases or decreases. (Also see fig. 9.2)
6. Where are the two lunar (tidal) bulges located with respect to Earth and the moon? (Also see fig. 9.7)
7. Describe the concept of an ideal ocean in Newton's explanation of the tides.
8. Explain why Hawai'i experiences two high tides and two low tides in approximately 24 hr. (Also see fig. 9.7)
9. Explain why the solar day is 24 hr whereas the lunar day is 24 hr 50 min. (Also see fig. 9.8, p. 526, and p. 532)
10. Where are the two solar (tidal )bulges located with respect to Earth and the sun? (Also see fig. 9.10)
11. Contrast the gravitation force of the Earth-Sun system with the Earth-Moon system.
12. Explain why the Sun's tidal bulges are only 46% the size of the Moon's tidal bulges, despite the Sun's much greater gravitational force.
13. Explain how the tide-generating force varies with distance.
14. Explain why the Moon exerts greater tide-generating forces on Earth.
15. Explain why Earth experiences flood tides and ebb tides. (Also see p. 521 and p. 522)
16. Give the length of the tidal month, the time required for Earth and the moon to revolve around each other once. (Also see fig. 9.11)
17. Give the relative positions of Earth and the moon during new moon, first-quarter moon, full moon, and third-quarter moon. (Also see fig. 9.10)
18. Define spring tide. (Also see fig. 9.10 and p. 532)
19. Define neap tide. (Also see fig. 9.10 and p. 527)
20. Define declination. (Also see fig. 9.12 and p. 520)
21. Define ecliptic. (Also see fig. 521)
22. Give the declination of the ecliptic. (Also see fig. 6.1 on p. 162)
23. Explain why Earth experiences seasons. (Also see fig. 6.1)
24. Give the declination of the Earth-Moon plane of revolution.
25. Use figures 9.12 and 9.14 to explain why Hawai'i experiences generally two unequal high tides and two unequal low tides in 24 hr and 50 min.