Physics I Class 17 Newtons Theory of Gravitation

Physics I Class 17 Newton’s Theory of Gravitation 1

Forces Known to Physics 2

Forces in Physics 1 (so far) 3

Newton’s Theory of Gravitation 4

Newton’s Law of Universal Gravitation 5

Properties of Gravity 6

If Gravity Varies As 1/r 2, Where Does g = 9. 8 m/s 2 Fit In? 7

Gravity is a Conservative Force 8

We Have Two Formulas for Gravitational Potential Energy! 9

Class #17 Take-Away Concepts 10

Class #17 Problems of the Day 11

Class #17 Problems of the Day 12

Activity #17 Gravitation 13

Class #17 Optional Material Part A - Kepler’s Laws of Orbits Material on Kepler’s Laws thanks to Professor Dan Sperber 14

Kepler’s Three Laws of Planetary Motion 1. The Law of Orbits: All planets move in elliptical orbits having the Sun at one focus. 2. The Law of Areas: A line joining any planet to the Sun sweeps out equal areas in equal times. 3. The Law of Periods: The square of the period of any planet about the Sun is proportional to the cube of the semi-major axis of its orbit. 15

Kepler’s Three Laws of Planetary Motion 16

The Law of Areas

The Law of Periods

ENERGY IN CIRCULAR ORBITS

Class #17 Optional Material Part B - General Relativity Material on General Relativity thanks to Albert Einstein 20

Where Did Newton Go Wrong? (Again!) 21

The Principle of Equivalence 22

The Principle of Equivalence 23

General Theory of Relativity 24

Black Holes 25

If Newton’s Gravity isn’t true, why do we still use it? Massive Black Holes In Galaxies NGC 3377, NGC 3379 And NGC 4486 B 26