ASTRO 7N - Unit 1, Part 1: Gravity Lesson
Mars has about 1/10 the mass of Earth and about 1/2 the radius of Earth. What is Mars' surface gravity compared to Earth?
0.4 times that of Earth
Saturn has about 100 times the mass of Earth and about 10 times the radius. What is the surface gravity of Saturn compared to Earth?
1
Law of Universal Gravitation
Fg = G (m₁ m₂) / r²
Mars has a lower surface gravity than Earth (True/False)
True
As the mass of the planet increases, the jump height _________ by the same factor as the mass.
decreases
Let's keep the mass Earth's mass but change the radius to twice the radius of Earth (2 R). How high do you jump?
four times as high
Now we can change the mass to 0.25 M. If we do, how much higher are you jumping?
four times as high
What is the relationship between gravity, mass, and radius? ("∝" means "proportional to")
g ∝ m/r²
How high are you jumping at twice Earth's mass (2 M) compared to Earth's mass?
half as high
As the radius of the planet increases, the jump height _________ as the square of the radius.
increases
Now we can change the mass to 0.5 M. If we do, how much higher are you jumping than at one Earth mass?
twice as high
Since the jump height is half as high, what does that tell us about the gravity?
twice as much
The Moon has about 1/100 the mass of Earth and about 1/4 the radius. What is the surface gravity of the Moon compared to Earth?
16/100
Jupiter has about 300 times the mass of Earth and about 10 times the radius. What is the surface gravity of Jupiter compared to Earth?
3
Let's keep the mass Earth's mass but change the radius to three times the radius of Earth (3 R). How high do you jump?
nine times as high
Keep the mass at Earth's mass but change the radius to half the radius of Earth (0.5 R). How much higher do you jump?
one-quarter as high