- 227 Views
- Uploaded on
- Presentation posted in: General

Friday: November 8, 2013

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Science In The News

- Describe the shape of a planetary orbit? What does it look like?
- Where is the Asteroid Belt located? By what planet?

Learning Target (LT) # 6Kepler’s Laws of Planetary Motion 11/08/13_____________________________Cornell StyleWrite only underlined text from slides33

- Found patterns in planet movement; developed 3 laws of planetary motion.

1. Law of Ellipses

2. Law of Equal Areas

3. Law of Periods

- The degree of elongation of an elliptical orbit.

1. Law of Ellipses: all orbits are elliptical, from nearly circular to parabolic.

e = 0e = 1

“e” is the eccentricity (how stretched to a max of “1”)

- Kepler’s second law states that equal areas are covered in equal amounts of time as an object orbits the sun.

2. Law of Equal Areas:

- Describes the speed of objects at different points.
- Objects move faster closer to perihelion and slower at aphelion.

- The time required for a body to complete a single orbit.

- Kepler’s first law states that each planet orbits the sun, not in a circle, but in an ellipse. TRUE or FALSE
- Kepler’s law that describes how fast planets travel at different points in their orbits is called the law of ____________.

Learning Target (LT) # 6Kepler and Newton 11/12/13_____________________________Cornell StyleWrite only underlined text from slides35

- Law of Periods:
- Relates the planets average distance from Sol to the time it takes the planet to complete 1 complete orbit.
- Measured in Earth years in distance of AU’s.
K x a3 = p2(K =1)

p = orbital period

a = distance from Sol

a3 = p2

Orbital periods measured = distance from the Sun.

Example: Jupiter’s orbital period is 11.9 Earth years

a3= p2

p=11.9

p2=142

p2=a3

a3=142

a=5.2

Jupiter’s average distance from Sol is 5.2 AU’s.

- Newton noticed that they also worked for all other objects. WHY?
- Inertia – tendency of object to resist change in motion unless outside force acts on it.

- But what force is causing the curve of the elliptical orbits, of a thrown ball, of a launched arrow…the apple falling from a tree?
- Objects in motion will stay in motion, unless…
Newton’s answer: Gravity!

Gravity is effected by distance and mass.

The closer the planet is to the sun, the stronger the gravity AND the faster the planet moves in its orbit,

In Review:

- Kepler’s 1st law states planets orbit the sun in curved paths called ellipses
- Kepler’s 2nd law states planets closer to the sun travel faster than those further away.
- Kepler’s 3rd law relates a planet’s average distance from around the sun to the time it takes to make one orbit.