$$6.67 \times 10$$^{-11}$$ \ \mathrm{N} \cdot \mathrm{m}^2 / \mathrm{kg}^2$$

Question 1

Which of the following best describes the Newtonian synthesis?

Accepted Answer

It states that the same set of laws apply to both celestial and terrestrial objects.

Question 2

According to the law of universal gravitation, what happens to the gravitational force between two objects if the distance between them is doubled?

Accepted Answer

The force becomes one-fourth as strong.

Question 3

Which equation correctly represents Newton's law of universal gravitation?

Accepted Answer

$$F = G \frac{m_1$ m_2$}{d^2$}$$

Question 4

What is the value and unit of the universal gravitational constant $$G$$?

Accepted Answer

$$6.67 	imes 10$$^{-11}$$ \ \mathrm{N} \cdot \mathrm{m}^2 / \mathrm{kg}^2$$

Question 5

A person stands on a scale in an elevator accelerating upward. What happens to the reading on the scale?

Accepted Answer

It increases compared to when the elevator is at rest.

Question 6

Why do astronauts in orbit experience weightlessness?

Accepted Answer

They are in a continual state of free fall, experiencing no support force.

Question 7

What causes ocean tides on Earth?

Accepted Answer

The gravitational attraction of the Moon and the Sun.

Question 8

During which lunar phases are spring tides most pronounced?

Accepted Answer

New Moon and Full Moon

Question 9

If the mass of one object is doubled and the distance between two objects is halved, how does the gravitational force change?

Accepted Answer

It increases by a factor of 8.

Question 10

Which of the following best describes a gravitational field?

Accepted Answer

An alteration of space around an object with mass, exerting a force on other masses.

Question 11

According to Einstein's theory of gravitation, what is gravity?

Accepted Answer

A warping of space-time by mass.

Question 12

What happens to the gravitational field strength as you move from the surface of the Earth toward its center?

Accepted Answer

It decreases, reaching zero at the center.

Question 13

A star collapses to half its original radius without losing mass. By what factor does the gravitational force at its surface change?

Accepted Answer

It increases by a factor of 4.

Question 14

Which of the following statements about black holes is correct?

Accepted Answer

A black hole forms when a collapsing star's gravitational field is so strong that not even light can escape.

Question 15

Which of the following is a consequence of the inverse-square law for gravity?

Accepted Answer

The gravitational force never reaches zero, even at great distances.

Question 16

Why is the Earth round according to the law of universal gravitation?

Accepted Answer

Gravity pulls all parts of Earth toward the center, making the surface equidistant from the center.

Question 17

Which of the following best describes a wormhole?

Accepted Answer

A hypothetical distortion of space-time that connects distant regions or universes.

Question 18

If you dig a hole through the Earth and jump in, what happens to your acceleration as you approach the center?

Accepted Answer

It decreases and becomes zero at the center.

Question 19

Which of the following is NOT a mystery currently associated with gravity?

Accepted Answer

The Earth's gravity is repulsive at large distances.

Chapter 9: Gravity – Study Notes

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