1. If there was a hole from here to the other side of the Earth and you placed a
stone in the center of the Earth, the stone will
a. Stay in the center of the Earth
2. If a huge gorilla slowed down the moon, the moon would
a. “Fall” and crash into the Earth
3. A difference between the force of gravity and the electromagnetic force is that
the force of gravity
a. Is only an attractive force, measured in N
4. Consider the gravitational force between the sun and Pluto in outer space. If
pluto moves so it is twice as far from the sun, the gravitational force of the sun
on Pluto will be
a. One quarter
5. If the sun were to disappear, Earth would
a. Leave the solar system in the direction of its tangential velocity
6. The least difference between high and low tides occurs when the moon is a
a. Half moon
7. If the mass of Earth doubled and the distance between the sun and Earth
doubled, the force of gravity between them would be __ times the original force
a. 1/2
8. During spring tides,
a. It may be possible to see a solar or lunar eclipse
9. If Earth’s mass decreased to one half its original mass, with no change in radius,
then your weight should
a. Decrease to 1/2 your original weight
10. Newton had the insight to see that a falling apple and the moon are
a. Both “falling” toward the Earth and both accelerating
11. If you weigh yourself in an elevator that is falling, compared to your ordinary
weight you would weigh
a. Less
12. The force due to gravity between two objects is ___ proportional to the distance
between them.
a. Inverse and exponentially
13. The gravitational force between you and an alien that is a billion miles awayis
a. Very tiny but not zero and dependent on the mass of the alien
True/False
14. If the sun were to collapse into a black hole, the Earth would still orbit as it is
now. True
15. If light crosses or enters past the event horizon (or boundary) of a black hole, it
*can* escape. False (Can not)
16. A kind of force field that surrounds massive objects is called a gravitational
force. True
17. If earth were its present size but had more mass, we would weigh *less*. False
(More)
18. The component of an orbiting satellite’s velocity parallel to Earth’s surface is
called its tangential velocity. True
19. As the mass of a planet increases, the sun’s force of gravity on the plan
*decreases*. False (Increases)
20. If the distance between the Earth and the moon decreases, the force of gravity
between them would increase. True
Tides
1. In the configuration above, if the moon was at A or C, what would the tides be
called?
a. If A and C are vertical then Neap tides. If A and C are horizontal then
Spring tides.
2. If you were to see a “lunar eclipse,” which position(s) (A,B,C, or D) would the
moon be in? (This is for when A and C are in horizontal)
a. C
3. If you were to see a “new or no moon”, at night, which position(s) (A,B,C, or D)
would the moon be in? (This is for when A and C are in horizontal)
a. A
4. In a 24 hour period how many high tides and low tides are there?
a. 2 High tides and 2 Low tides
5. State which has a greater effect on the tides, the sun or the moon, and explain
why. (Whatever is closer has a greater effect)
a. Moon - Closer
Chart Directions
Use formula to figure it out
First row if it says halve, just half the Fg Initial value
Second row if it says double, just double the Fg initial value
Third row if R has times 5, then use formula
Fourth row if R has times 1/3 then use formula
Problems
10. Calculate the man’s weight
a. 26 N
11. How far from the center of Mars is the man?
a. 5.46 x 10^6 m