Universal Gravitation Practice Problems
Name:
Period:
Physics
Body
Mass (kg)
Sun
Mercury
Venus
Earth
Moon
Mars
Jupiter
Io
Saturn
Titan
Uranus
Neptune
Pluto
Charon
1.99 x 1030
3.30 x 1023
4.87 x 1024
5.97 x 1024
7.35 x 1022
6.42 x 1023
1.90 x 1027
8.89 x 1022
5.69 x 1026
1.34 x 1023
8.66 x 1025
1.03 x 1026
1.50 x 1022
7.35 x 1020
Radius (km) Orbital Radius (km)
696,000
2440
6052
6378
1738
3397
71492
1815
60268
2575
25559
24764
1151
600
57,895,000
108,161,000
149,600,000
384,000
227,392,000
778,300,000
422,000
1,427,000,000
1,221,830
2,884,000,000
4,521,000,000
5,959,000,000
19,700
Orbital Period
87.96 days
224.7 days
365.26 days
27.32 days
686.98 days
11.86 years
1.77 days
29.46 years
15.95 days
84.01 years
164.8 years
248.6 years
6.39 days
1. Why is it called Newton’s Law of Universal Gravitation?
2. What factors determine how strong the gravitational force between two objects is? How are they
related to the strength of the gravitational force?
3. a) Convert your weight from lbs to Newtons. (1 lb = 4.45 N)
b) Use the universal law equation for the force of gravity here on earth to figure out your mass.
c) Based on Newton’s Law of Universal Gravitation, how much would you weigh on Mercury?
d) How much would you weigh on Jupiter?
c) How much would you weigh on Saturn?
d) How much would you weigh on Pluto?
4. a) What is the force of gravity between a 1,000,000,000 kg asteroid and the earth when the asteroid
is 3,000,000 m away from the earth?
b) How quickly will the asteroid accelerate because of that force? (Use Newton’s 2nd Law)
5. What is the force of gravity between a 100 kg astronaut and a 50 kg astronaut floating 2 m apart in
deep space?
b) How quickly will each astronaut accelerate because of that force? (Find 2 accelerations)
6. a) How strong is the gravitational force between Mercury and the sun?
b) How strong is the gravitational force between Uranus and the sun?
c) Which force has a greater gravitational force from the sun acting on it? Is that surprising? Why or
why not?