5.6 Newton’s Law of Universal Gravitation

5.7 Gravity Near the Earth’s Surface

5.8 Satellites and Weightlessness

5.9 Kepler’s Laws and Newton’s Synthesis

Objectives:

1.  Students will explain how the law of universal gravitation is affected by mass and distance.

2.  Students will distinguish “G” from “g.”

3.  Students will explain the concept of “weightlessness.”

4.  Students will relate the law of universal gravitation to satellite orbits.

Homework: 29-39, 43-53, 57-61 odd pages 131-133

Formula Search – Find all formulas and state the units and purpose for making calculations.

Vocabulary to Know:

Gravity Satellites Foci

Force Weightlessness Period

Gravitational Force Geosynchronous Perturbations

Acceleration Tangential Speed

Radius Ellipse

5.6 Newton’s Law of Universal Gravitation

1. What was Newton’s motivation for developing the law of universal gravitation?

2. What was the difference between Newton’s gravitational force and the definition of force in his day?

3. What concepts did Newton focus on when developing the law of universal gravitation?

4. What is meant by an inverse square law?

5. Explain the law of universal gravitation.

6. Why is the universal constant “G” so small and how was it calculated?

7. Why is Newton’s second law unlike the law of universal gravitation?

5-7 Gravity Near the Earth’s Surface; Geophysical Applications

1. For what other variables can the law of universal gravitation be used in order to better understand or explain physical traits?

2. Why does the value of “g” vary on the earth?

5-8 Satellites and “Weightlessness”

1. How is a satellite put into orbit?

2. How does a satellite stay in orbit?

3. How is a geosynchronous orbit created?

4. Compare and contrast “+g” and “-g.”

5. Why is there truly no weightlessness?

5-9 Kepler’s Laws and Newton’s Synthesis

1. What is the function of Kepler’s laws?

2. List and explain each of Kepler’s laws.

3. When can we apply Kepler’s laws and when can we not use the laws?

4. What was Newton’s explanation for elliptical orbits?

5. How did the understanding of perturbations advance astronomical studies?