Universal Gravitation

1. Universal Gravitation • Newton hypothesized that the moon: • is a projectile • is actually attracted to Earth • is falling around Earth • has tangential velocity that prevents it from falling into earth • all of the above

2. Universal Gravitation • If the radius of Earth decreased, with no change in mass, your weight would: • increase • not change • decrease

3. Universal Gravitation • A very massive object A and a less massive object B move toward each other under the influence of mutual gravitation. Which force, if either, is greater? • the force on A • the force on B • both forces are the same

4. Universal Gravitation • A very massive object A and a less massive object B move toward each other under the influence of mutual gravitation. Which object will accelerate more? • object A • object B • both objects accelerate the same

5. Universal Gravitation • The force of gravity on you is greatest when you are standing: • above the earth’s surface • at the center of the earth • on the earth’s surface

6. Universal Gravitation • Consider the gravitational force between the earth and a meteor in outer space. If the meteor moves so its distance from the earth’s center doubles, the gravitational force on the meteor will be: • one quarter • half • double • quadruple

7. Universal Gravitation • Why did Newton think there was a force acting on the moon? • because the moon always keeps one side toward Earth • because the moon moves in a curved path • because there is no air on the moon • because the moon is moving • all of the above

8. Universal Gravitation • Suppose the gravitational force between two masses is 10 newtons. If the volume of each mass doubles, while everything else stays the same, what is the force between the masses? • 40 N • 20 N • 10 N • 5 N • 2.5 N

9. Universal Gravitation • The force of attraction between two masses depends inversely on the square of the distance between them. Any law that follows this relationship is called an inverse square law. • true • false

10. Universal Gravitation • Because Earth is “falling” around the sun, it will eventually crash into it. • true • false

11. Gravitational Interactions • The value of the acceleration due to gravity: • depends on the radius of Earth • depends on the mass of Earth • depends on the universal gravitational constant • is different on different planets • all of the above

12. Gravitational Interactions • Gravitational field lines show the: • direction a mass would be accelerated • direction of the field • direction of the force on any mass • strength of the field • all of the above

13. Gravitational Interactions • The acceleration due to gravity at the center of the earth is: • large • the same as on the surface • slightly less than on the surface • zero

14. Gravitational Interactions • If you were to weigh yourself in an elevator that is accelerating upward, compared to your ordinary weight you would weigh: • more • the same • less, but more than zero • zero

15. Gravitational Interactions • The affect of the sun’s pull on the earth’s oceans is much less visible that that of the moon’s pull because: • Earth is orbiting so fast • Earth is rotating so fast • the sun is so far away • the sun is radiating a lot of energy • none of the above

16. Gravitational Interactions • A lunar eclipse occurs when: • the sun is between Earth and the moon • the moon is between Earth and the sun • Earth is between the moon and the sun

17. Gravitational Interactions • When a star collapses to form a black hole, its mass: • undergoes an enormous increase • decreases • remains the same

18. Gravitational Interactions • The factor most directly responsible for making a black hole invisible is: • size • mass • color • not even light can escape • none of the above