3.12.2: Thought Questions
Thought Questions
Is it possible to escape the force of gravity by going into orbit around Earth? How does the force of gravity in the International Space Station (orbiting an average of 400 km above Earth’s surface) compare with that on the ground?
20.
What is the momentum of an object whose velocity is zero? How does Newton’s first law of motion include the case of an object at rest?
21.
Evil space aliens drop you and your fellow astronomy student 1 km apart out in space, very far from any star or planet. Discuss the effects of gravity on each of you.
22.
A body moves in a perfectly circular path at constant speed. Are there forces acting in such a system? How do you know?
23.
As friction with our atmosphere causes a satellite to spiral inward, closer to Earth, its orbital speed increases. Why?
24.
Use a history book, an encyclopedia, or the internet to find out what else was happening in England during Newton’s lifetime and discuss what trends of the time might have contributed to his accomplishments and the rapid acceptance of his work.
25.
Two asteroids begin to gravitationally attract one another. If one asteroid has twice the mass of the other, which one experiences the greater force? Which one experiences the greater acceleration?
26.
How does the mass of an astronaut change when she travels from Earth to the Moon? How does her weight change?
27.
If there is gravity where the International Space Station (ISS) is located above Earth, why doesn’t the space station get pulled back down to Earth?
28.
Compare the density, weight, mass, and volume of a pound of gold to a pound of iron on the surface of Earth.
29.
If identical spacecraft were orbiting Mars and Earth at identical radii (distances), which spacecraft would be moving faster? Why?