Question

Section 12.2 Newton’s First and
Second Laws of Motion
(pages 363–369)
This section discusses how force and mass affect acceleration. The acceleration
due to gravity is defined, and mass and weight are compared.
Reading Strategy (page 363)
Building Vocabulary As you read this section, write a definition in
the table for each vocabulary word you encounter. Use your own
words in the definitions. For more information on this Reading
Strategy, see the Reading and Study Skills in the Skills and
Reference Handbook at the end of your textbook.
Matter and Motion
Vocabulary
Definition
Inertia
Aristotle, Galileo, and Newton (pages 363–364)
Match each scientist with his accomplishment.
Accomplishment
Scientist
1. Italian scientist who did experiments
that helped correct misconceptions
about force and motion
2. Scientist who studied in England and
introduced several laws describing
force and motion
3. An ancient Greek philosopher who
made many scientific discoveries
through observation and logical reasoning
Newton’s First Law of Motion (pages 364–365)
4. Is the following sentence true or false? According to Newton’s first
law of motion, an object’s state of motion does not change as long as
the net force acting on it is zero.
5. What is inertia?
© Pearson Education, Inc., publishing as Pearson Prentice Hall. All rights reserved.
Physical Science Guided Reading and Study Workbook
■
Chapter 12 105
a. Aristotle
b. Galileo
c. Newton

6. Is the following sentence true or false? The law of inertia states
that an object in motion will eventually slow down and come to a
complete stop if it travels far enough in the same direction.
Newton’s Second Law of Motion (pages 365–368)
7. According to Newton’s second law of motion, acceleration of an
object depends upon the
of the object and
the
acting on it.
Match each term with its description.
Description
Term
8. A measure of the inertia of an object
9. Net force/Mass
10. Causes an object’s velocity to change
11. Is the following sentence true or false? The acceleration of an
object is always in the same direction as the net force acting on
the object.
12. Is the following sentence true or false? If the same force acts upon
two objects with different masses, the acceleration will be greater
for the object with greater mass.
Weight and Mass (pages 368–369)
13. What is weight?
14. Write the formula used to calculate the weight of an object.
15. Is the following sentence true or false? Because the weight formula
shows that mass and weight are proportional, doubling the mass
of an object will not affect its weight.
16. Complete the table below by describing the difference between
mass and weight.
Mass and Weight
Mass
Weight
17. On the moon, the acceleration due to gravity is only about one sixth
that on Earth. Thus, an object will weigh

Answer 1

Here are concise answers for Section 12.2:

Vocabulary
- Inertia: The tendency of an object to resist changes in its motion (to stay at rest or keep moving at constant velocity); depends on mass.

Aristotle, Galileo, and Newton (pages 363–364)
Match:
1. Italian scientist who did experiments that helped correct misconceptions about force and motion — b. Galileo
2. Scientist who studied in England and introduced several laws describing force and motion — c. Newton
3. An ancient Greek philosopher who made many scientific discoveries through observation and logical reasoning — a. Aristotle

Newton’s First Law of Motion (pages 364–365)
4. True. An object’s state of motion does not change as long as the net force acting on it is zero.
5. Inertia is an object’s resistance to changes in its motion (how much it resists acceleration); it depends on mass.
6. False. The law of inertia says an object in motion stays in motion at constant velocity unless a net force acts on it; it does not say it will eventually stop on its own.

Newton’s Second Law of Motion (pages 365–368)
7. Acceleration depends upon the mass of the object and the net force acting on it.

Match each term with its description:
8. A measure of the inertia of an object — Mass
9. Net force/Mass — Acceleration (a = Fnet / m)
10. Causes an object’s velocity to change — Net force (or force)
11. True. Acceleration is always in the same direction as the net force acting on the object.
12. False. If the same force acts on two objects, the object with smaller mass has the greater acceleration.

Weight and Mass (pages 368–369)
13. Weight is the gravitational force on an object (the force due to gravity acting on its mass).
14. Weight formula: W = m g (weight = mass × acceleration due to gravity)
15. False. Mass and weight are proportional, so doubling mass doubles weight.
16. Mass and Weight
- Mass: Amount of matter in an object; scalar; does not change with location; SI unit = kilogram (kg).
- Weight: Force of gravity on an object; depends on local gravity; changes with location; SI unit = newton (N) (W = mg).

17. On the moon (g ≈ 1/6 that of Earth), an object will weigh one-sixth as much as it does on Earth.