Transcript Ellipse

Aim: What are the shapes of the planets’
orbits around the sun and their affect on
orbital speed?
I. Revolution – the movement of one
body around another body. An orbit is the
path taken by one body as it revolves
around the other body.
A. Focus – a fixed, central point. A
circle has one focus.
B. Ellipse – A flattened circular path
that has two foci (fixed points).
What is the difference between Revolution
and rotation? Morgan, what are your
thoughts?
Excellent Morgan!!! Revolution is the
movement of a planet around the sun, and
rotation is the spinning of a planet on its
axis.
C. Eccentricity – the roundness of a circle
1. Eccentricity = distance between foci
length of major axis
Major axis
Foci
II. Orbital Velocity – time per distance of
a planet’s path around the sun.
A. A planet’s orbital velocity changes
throughout its orbit.
Perihelion
Earth
Aphelion
Sun
1. A planet’s orbital velocity is greatest
when it is at its perihelion (point in orbit
where a planet is closest to the sun).
2. A planet’s orbital velocity is least when
it is at its aphelion (point in orbit where a
planet is furthest from the sun).
Q. What is eccentricity?
Mr. Goldman, please try to answer the question.
Great job Brandon!! Eccentricity refers to
how round a circle is.
Q. What is the difference between aphelion
and perihelion?
Ms. Pattwell, I know you want to answer this
one. Please stand up and give us your
answer.
Who is smarter than you? Yes, aphelion is the
point in a planet’s orbit in which it is furthest
from the sun, and perihelion is when it is
closest to the sun.
One more question!!!
Q. What is the formula for eccentricity?
I’m going to cry! You have come so far this
year. Yes, eccentricity equals the distance
between the foci divided by the major axis.