Lesson 2: Orbits
Overview:
If gravity is so attractive, why doesn't the earth just crash into the sun? Or the moon into the earth?
In this lesson we will explore this question, and describe how we keep satellites in a special type of orbit that helps us with telecommunications.
In this lesson we will explore this question, and describe how we keep satellites in a special type of orbit that helps us with telecommunications.
Curriculum Expectations:
Overall Expectations:
D1. Analyze the operation of technologies that use gravitational, electric, or magnetic fields, and assess the technologies’ social and environmental impact.
D2. Investigate, in qualitative and quantitative terms, gravitational, electric, and magnetic fields, and solve related problems.
Specific Expectations:
D1.1 Analyze the operation of a technological system that uses gravitational, electric, or magnetic fields (e.g., a home entertainment system, a computer, magnetic strips on credit cards).
D2.1 Use appropriate terminology related to fields, including, but not limited to: forces, potential energies, potential, and exchange particles.
D2.2 Analyze, and solve problems relating to, Newton’s law of universal gravitation and circular motion (e.g., with respect to satellite orbits, black holes, dark matter).
D1. Analyze the operation of technologies that use gravitational, electric, or magnetic fields, and assess the technologies’ social and environmental impact.
D2. Investigate, in qualitative and quantitative terms, gravitational, electric, and magnetic fields, and solve related problems.
Specific Expectations:
D1.1 Analyze the operation of a technological system that uses gravitational, electric, or magnetic fields (e.g., a home entertainment system, a computer, magnetic strips on credit cards).
D2.1 Use appropriate terminology related to fields, including, but not limited to: forces, potential energies, potential, and exchange particles.
D2.2 Analyze, and solve problems relating to, Newton’s law of universal gravitation and circular motion (e.g., with respect to satellite orbits, black holes, dark matter).
Success Criteria:
 What is the difference between natural and artificial satellites? Give an example of each.
 Explain what microgravity is.
 Explain in your own words how GPS satellites work.
 Is the Moon's orbit around Earth circular?
 What is a geosynchronous orbit? How does a satellite in geosynchronous orbit appear to an observer on Earth? How does a satellite in geostationary orbit appear to an observer on Earth?
 Derive the equation for the orbital speed of a satellite around a mass M.
Time Allocation: 4 hours
Learning A
ctivities:Read pages 297  302 from Nelson 6.2 and copy the sample problems into your notes.
In the playlist below, video:
 Will calculate the acceleration (and weight) of a satellite in orbit.
 Will explain and calculate Kepler's 3rd Law.
 Will show you how to calculate the orbital velocity at various heights.
 Will show you how to calculate the height for a satellite at geosynchronous orbit.
Practice questions 1, 2, and 3 on page 302.
Task:
Solve questions 8, 9, and 10 from Nelson 6.2 Review on page 303.
Quiz Chapter 6 on Moodle.
Optional Extension:
Quiz Chapter 6 on Moodle.
Optional Extension:
 Solve questions 12 and 14 on page 303.
Reflect:

If gravity is so attractive, why doesn't the earth just crash into the sun? Or the moon into the earth?
The answer: Stable Orbits 