1. THIS PRESENTAION HAS BEEN RATED BY THE CLASSIFICATION AND RATING ADMINISTRATION TG-13 TEACHERS’ GUIDANCE STRONGLY ADVISED Some Material May Be Unintelligible For Students Under 13. Intense Frames of Scientific Instruction, Analysis, Comparing and Contrasting, Description, and for Some Vocabulary. © 1852 All Rights Reserved VOID WHERE PROHIBITED BY LAW

2. The authorized reproduction or distribution of this copyrighted work is highly encouraged. Lethargic obtuseness is insubordinate and is discouraged by PBIS, as it may result in little or no monetary gain after secondary education or a fine of $250,000. © 1852 All Rights Reserved VOID WHERE PROHIBITED BY LAW PBIS ANTI-VACUITY

3. ASTRONOMY ORBITAL MECHANICS

4. OBJECTIVES By the end of this presentation, students will be able to Evaluate the relative force of gravity on the surface of a planet using Newton’s Law of Universal Gravity. Evaluate the relative force of gravity between a star and a planet using Newton’s Law of Universal Gravity.

5. The force of attraction between any two objects is directly proportional to the product of the two masses and inversely proportional to the square of the radius between them. F g = G m 1 m 2 R 2 NEWTON'S UNIVERSAL LAW OF GRAVITATION:

6. Experiments show that if F is measured in Newtons, m 1 and m 2 are measured in kilograms and R is measured in meters, G, the Universal Gravitational Constant, then has the value G = 6.67 x 10 -11 Nm 2 /kg 2

7. Earth’s gravity has a certain hold on objects on its surface. How much force would hold objects on a planet that is the same size but three times as massive? F g is directly proportional to the product of the masses. Three time the mass, yields three times the force.

8. Earth’s gravity has a certain hold on objects on its surface. How much force would hold objects on a planet that is the same size but five times as massive? F g is directly proportional to the product of the masses. Five time the mass, yields five times the force.

9. Earth’s gravity has a certain hold on objects on its surface. How much force would hold objects on a planet that is the same size but half as massive? F g is directly proportional to the product of the masses. Half of the mass, yields half the force.

10. Earth’s gravity has a certain hold on objects on its surface. How much force would hold objects on a planet that is twice the size but has the same mass? F g is inversely proportional to the square of the distance between the mass’ centers. Twice the distance, yields one-fourth the force. (1/2) 2

11. Earth’s gravity has a certain hold on objects on its surface. How much force would hold objects on a planet that is four times the size but has the same mass? F g is inversely proportional to the square of the distance between the mass’ centers. Four times the distance, yields one- sixteenth the force. (1/4) 2

12. Earth’s gravity has a certain hold on objects on its surface. How much force would hold objects on a planet that is one-third the size but has the same mass? F g is inversely proportional to the square of the distance between the mass’ centers. One-third the distance, yields nine times the force. (1/⅓) 2 = (3) 2

13. Earth’s gravity has a certain hold on objects on its surface. How much force would hold objects on a planet that is twice the size AND has the twice the mass? F g is inversely proportional to the square of the distance between the mass’ centers. Twice the distance, yields one-fourth the force. (1/2) 2

14. Earth’s gravity has a certain hold on objects on its surface. How much force would hold objects on a planet that is twice the size AND has the twice the mass? F g is directly proportional to the product of the two masses. Twice the mass, yields twice the force. 2 x ¼ = ½; half the force.

15. ASTRONOMY ORBITAL MECHANICS