ASTRO 7N Unit 1 Part 1: Gravity Lesson

Experiment using Mars' and Earth's gravity to see what effect they have on gravity. What is its surface gravity compared to Earth? (Mars has about 1/10 the mass and 1/2 the radius of Earth)

0.4 times

Saturn has about 100 times the mass of Earth and 10 times the radius. What is the surface gravity of Saturn compared to Earth?

1

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 10 times the radius. What is the surface gravity of Jupiter compared to Earth?

3

As the mass of the planet increases, the jump height _______ by the same factor as the mass.

Decreases

Let's keep the mass at Earth's mass but change the radius to twice the radius of earth. How high do you jump?

Four times as high

Now we can change the mass to 0.25M. If we do, how much higher are you jumping?

Four times as high

How high are you jumpting at twice Earth's mass 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

Let's keep the mass at Earth's mass but change the radius to three times the radius of the earth. How high do you jump?

Nine times as high

Let's keep the mass at Earth's mass but change the radius to half the radius of the earth. How much higher do you jump?

One-quarter as high

Now we can change the mass to 0.5M. 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 gravity?

Twice as much. (More gravity = lower jump height)

What is the relationship between gravity, mass and radius?

g ∝ m/r^2