The acceleration due to gravity, “g”
𝑔=𝐺
𝑚
𝑑2
G = 6.67 x 10-11
1. If the mass of the Earth were to double with no change in its radius, by what factor would your weight
change?
2. If the radius of the Earth were to double with no change in its mass, by what factor would your weight
change?
3. If the radius of the Earth were half as much with no change in its mass, by what factor would your weight
change?
4. If you were on a planet whose mass with 8 times Earth’s mass and whose radius was twice Earth’s radius, by
what factor would your weight change?
Find the acceleration due to gravity, “g”, for the following planets (and the Moon) and then calculate the weight
of a 75 kg person on that planet.
5. The Moon, m = 7.36 x 1022 kg, radius = 1.74 x 106 m
6. Mars, m = 6.4 x 1023 kg, radius = 3.395 x 106 m
7. Jupiter, m = 1.9 x 1027 kg, radius = 7.15 x 107 m
8. Pluto, m = 1.2 x 1022 kg, radius = 1.15 x 106m
9. Earth, m = 5.98 x 1024 kg, radius = 6.37 x 106
Gravitational Force Assignment
𝐹=𝐺
G = 6.67 x 10 -11
𝑚1 𝑚2
𝑑2
1. What is the gravitational force of attraction between a dog of mass 15 kg and a cat of mass 2 kg if they are 2
meters apart?
2. What is the gravitational force of attraction between a young man of mass 60 kg and a young woman of mass
55 kg if they are standing 1 meter apart?
3. What is the gravitational force of attraction between the Earth, m = 5.98 x 1024 kg and the moon,
m = 7.36 x 1022 kg if the distance between them is 3.82 x 108 m?
4. What is the gravitational force of attraction between the Earth and the Sun, m = 1.99 x 1030 kg, if the distance
between them is d = 1.5 x 1011 m?
5. If the gravitational force between a 200 kg mass and a 500 kg mass is 3.0 x 10-4N, how far apart are they?
6. If the gravitational force between a 350 kg mass and an 825 kg mass is 2.4 x 10-3N, how far apart are they?
7. If the distance between 2 objects doubles, what happens to the gravitational force between them?
8. If the distance between 2 objects in halved, what happens to the gravitational force between them?
9. If the mass of both objects doubles, what happens to the gravitational force between them?
10. If one mass is doubled AND the distance is doubled, what happens to the gravitational force?