Download Example: The gravitational force of attraction between Earth and the

Newton’s Universal Law of Gravitation (HON)
1. Suppose that two objects attract each other with a force of 16 Newtons. If the distance
between the two objects is doubled and the mass of one object is doubled, what is the new
force of attraction between the two objects? (8 N)
2. Suppose that two objects attract each other with a force of 16 Newtons. If the distance
between the two objects is reduced in half and the mass of one object is reduced in half, then
what is the new force of attraction between the two objects? (32 N)
3. Suppose that two objects attract each other with a force of 16 Newtons. If the distance
between the two objects is 1/3 the original distance, the mass of one object is doubled, and
the mass of the second object is tripled, then what is the new force of attraction between the
two objects? (864 N)
4. A puppy and cat have a gravitational force of 5x10-13 N between them. If the distance
between them triples and the puppy grows to quadruple its mass then what is the new
gravitational force between the two objects? (2.22x10-13 N)
5. If you wanted to make a profit in buying gold by weight at one altitude and selling it at another
altitude for the same price per weight, should you buy at the higher or lower altitude location?
Should you sell at the higher or lower altitude location? (Think about how altitude will affect the
weight of the gold.)
6. The Earth and moon are located 3.844x108 m away from each other and the gravitational force
between them is 2x1020 N. Using the mass of the Earth, 6x1024 kg, determine the mass of the moon.
(7.36x1022 kg)
7. A person with a mass of 80kg is standing on the Earth. The weight of the person is 782 N and the
mass of the Earth is 6.0x1024 kg. What is the distance between the person and the center of the
Earth? (6.4x106 m) in kilometers? (6400km)
8. True or False: A gravitational force only exists between large bodies (like planets) and other objects.
9. True or False: There is no gravity on the moon.
10. A gravitational force exists between Earth and Jupiter. This gravitational force is between
a. The center of Earth and the center of Jupiter.
b. The surface of Earth and the surface of Jupiter.
c. The surface of Earth and the center of Jupiter.
11. Would a greater gravitational force exist between
a. a DVD and TV or
b. a DVD and house
Why did you choose this answer?
12. Would a greater gravitational force exist between
a. a man on top of Mt. Everest and Earth or b. a man orbiting Earth in a space shuttle and Earth
Why did you choose this answer?
13. A 70 kg boy stands at the top of Mt. Everest, which is 8848 m above the surface of the Earth.
The Earth has a radius of 6378100 m and a mass of 6 x 1024 kg. What is the gravitational force
between the Earth and man? (Ans: 686.7 N… the answer is NOT 688.6 N)
14. Three cars (A, B, and C) are lined up in a row each 3 m apart in outer space. The masses are as
follows: A = 500 kg, B = 1200 kg, C = 800 kg. Draw a picture of the situation and draw the
gravitational forces acting on car B from A and C (free-body diagram for car B), then calculate the
net gravitational force acting on car B. (2.67 x 10-6N)
Planet
Mercury Venus
Earth
Mars
Jupiter
Saturn
Uranus
Neptune
mass
3.3x1023 4.87x1024 5.98x1024 6.42x1023 1.90x1027 5.69x1026 8.68x1025 1.02x1026
(kg)
diameter 4,878
12,104
12,756
6,787
142,796 120,660 51,118
48,600
(km)
Directions: Refer to the chart above to answer questions 15-17.
15. What is the acceleration due to gravity on the surface on Earth? Use the values in the table
above to verify this.
16. a. What would be the acceleration due to gravity experienced by an 1800 kg satellite orbiting
Earth 1000 km above Earth’s surface? (7.3 m/s2)
b. How high above Earth’s surface would the satellite have to be to experience an acceleration
due to gravity of 1 m/s2? (13,593 km)
17. What would be the gravitational force experienced by a 1000 kg object at an altitude of 200km
above Mars’ surface? (Hint: remember gravity is measured from the center of objects and altitude is
just the distance from the surface not the center) (3316 N)
18. Trivia Question: What is the closest star to Earth?
19. The Sun has a mass of 2 x 1030 kg and a radius of 6.96 x 108 m. What would be the acceleration
due to gravity experienced at the surface of the sun if something could actually get that close to it
before burning up? How would this acceleration compare to the accelerations due to gravity on
other planets? (275 m/s2)
20. The gravitational force experienced by an astronaut who is 2 x 109m away from the center of a
sun is 2000 N. Suddenly the sun (similar in size to ours) collapses into a black hole with radius
10m. What is the gravitational force experienced by the same astronaut at his original location?
21. A gravitational force of 10 N exists between 2 objects. If the mass of one object is halved, the
mass of the other is tripled, and the distance between them is 1/4 the original distance, then what is
the new gravitational force between them. (Ans: 240N)
22. Mercury orbits the sun because of a gravitational force of 1.31 x 1020 N. The mass of the sun is
2 x 1030 kg. On average how many kilometers is Mercury from the sun? (Ans: 5.8 x 108 km)
23. The distance between a baseball and bat is reduced by 1/3. How many times greater will the
gravitational force be? (9 times greater)