Universal Law of Gravitation Worksheet
Newton's Universal Law of Gravitation (first stated by Newton): any two masses
m1 and m2 exert an attractive gravitational force on each other according to
m1 m 2
F  G
r2
m1 F
F
m2
r
This applies to all masses, not just big ones.
G = universal constant of gravitation = 6.67  10–11 N m2 / kg2 (G is very
small, so it is very difficult to measure!) Don't confuse G with g: "Big G" and
"little g" are totally different things.
Practice problems:
1. Consider a space shuttle which has a mass of about 1.0 x 105 kg and circles
the Earth at an altitude of about 200.0 km. Calculate the force of gravity that
the space shuttle experiences. The mass of the earth is
2. What is the gravitational force between two identical 50,000 kg asteroids
whose centers of mass are separated by 1000 m?
3. If you have a mass of 55 kg and you are standing 3 meters away from your
car, which has a mass of 1234 kg, how strong is the force of gravity between
you and the car?
4. The moon has a mass of 7.34  10 22 kg and a radius of 1.74  106 meters. If
you have a mass of 66 kg, how strong is the force between you and the
moon?
5. Romeo is a 68 kg astronaut. Juliet is a beautiful cosmonaut who is standing
on the balcony of a 4.58  105 kg space station that is at rest and out of gas.
Romeo is floating 25 meters away from the space station’s center of mass,
how strong is the force between Romeo and Juliet?
Universal Law of Gravitation Worksheet
Newton's Universal Law of Gravitation (first stated by Newton): any two masses
m1 and m2 exert an attractive gravitational force on each other according to
m1 m 2
F  G
r2
m1 F
F
m2
r
This applies to all masses, not just big ones.
G = universal constant of gravitation = 6.67  10–11 N m2 / kg2 (G is very
small, so it is very difficult to measure!) Don't confuse G with g: "Big G" and
"little g" are totally different things.
Practice problems:
1. Consider a space shuttle which has a mass of about 1.0 x 105 kg and circles
the Earth at an altitude of about 200.0 km. Calculate the force of gravity that
the space shuttle experiences. The mass of the earth is
2. What is the gravitational force between two identical 50,000 kg asteroids
whose centers of mass are separated by 1000 m?
3. If you have a mass of 55 kg and you are standing 3 meters away from your
car, which has a mass of 1234 kg, how strong is the force of gravity between
you and the car?
4. The moon has a mass of 7.34  10 22 kg and a radius of 1.74  106 meters. If
you have a mass of 66 kg, how strong is the force between you and the
moon?
5. Romeo is a 68 kg astronaut. Juliet is a beautiful cosmonaut who is standing
on the balcony of a 4.58  105 kg space station that is at rest and out of gas.
Romeo is floating 25 meters away from the space station’s center of mass,
how strong is the force between Romeo and Juliet?