Convert 626,000,000 into scientific notation.
6.26x108
Planets typically have orbits of this shape.
Elliptical

Arc AB: 6-month travel time.
Arc CD: 6-month travel time.
How does the area of slice AB compare to slice CD?
They are EQUAL areas.
Formula for Universal Law of Gravitation
Fg = Gm1m2 / d2
Planets that are closer to the central mass move ___________ than planets further from the central mass.
faster
Convert 0.00005634 to scientific notation.
5.634 x 10-5
The two points within an ellipse which define the structure of the shape are called...
foci (focus points)

If sectors AB and CD are equal areas, which arc takes longer for the planet to travel across? AB or CD?
TRICK QUESTION! The planet will travel over both arcs in the SAME amount of time!
Doubling (2x) one of the masses will change gravitational force by:
2x
Planet A's velocity changes a lot over its orbit.
Planet B's velocity changes very little over its orbit.
Which planet has a more circular orbit?
Planet B
6.02x1023 x 3.4x108
2.05x1032
Ellipse A has an eccentricity of 0.01.
Ellipse B has an eccentricity of 0.9.
Which is MORE circular?
A!
(A perfect circle has an eccentricity of 0)
Kepler's 3rd Law formula
T2 = R3
T2/R3 = 1
Doubling (2x) distance will change gravitational force by:
1/4x
(0.25x)
Two moons orbit a planet at the same distance.
Moon A is twice the mass as Moon B.
Compared to Moon B, Moon A's velocity is ?-times (?x) the velocity of Moon B.
1x (SAME! Remember, the orbiting mass does NOT matter!)
6.02x1023 / 3.4x108
1.77x1015
The Sun represents one of the two foci of Earth's elliptical orbit. What is located at the other focus point in space?
NOTHING!
Astronomical Units (AUs)
If one mass quadruples (4x) and the other mass halves (1/2x) and the distance between them doubles (2x), the force of gravity will change by...
0.5x
(1/2x)
You’re given the orbital velocities for two identical moons that are orbiting DIFFERENT planets at the SAME distance.
Moon 1 moves at 2,000m/s.
Moon 2 moves at 3,000m/s.
Based on this information, which moon is orbiting the larger planet?
Moon 2
PLACE YOUR BET!
You can wager as little as zero points, or as much as your current score!
You will gain this amount if you get the question right.
You will lose this amount if you get the question wrong.
BETS PLACED! IT'S TIME FOR THE QUESTION!
(5.78x1018)2
3.34x1037
A straight line
An asteroid is found in our Solar System. The asteroid takes 3 Earth years to travel around the Sun. Would it be possible for this asteroid to orbit the Sun at a distance of 4 AU?
NO! T2/R3 = (3)2/(4)3 = 0.14, or NOT 1!!
A planet with a mass of 6.2x1024kg orbits a star with a mass of 5.8x1032. If the distance between them is 4.5x106m, what is the force of gravity that they experience from each other? (DON'T forget units!)
1.18X1034 N
Youre given two orbital velocities for moons that are orbiting the SAME planet.
Moon 1 moves at 2,000m/s.
Moon 2 moves at 3,000m/s.
Based on this information, which moon has a shorter orbital radius?
Moon 2
Earth's orbit is shown in YELLOW.
If Jupiter was placed where Earth is, and moved at the same velocity as Earth, WHERE would Jupiter be in 6 months?
(Jupiter is 11x the size of Earth, and about 318x more massive.)

C: the SAME place Earth would be in 6 months!