# Force and Motion

An Illustrated Guide to Newton's Laws

Publication Year: 2009

Published by: Johns Hopkins University Press

#### Cover

#### Frontmatter

#### Preface

Newtonian mechanics, the subject of this book, is no longer considered a fundamental theory of nature.We live in a world of quantum theory and nanotechnology. But ask a physicist of today, even a quantum physicist, to explain how a curve ball works, and he or she will certainly use the methods and concepts of Newtonian mechanics to do so. Newtonian...

#### 1 Graphing Relationships

Being comfortable with graphs is a basic requirement for citizenship
in modern society. To become knowledgeable about issues
such as global climate change, for example, we have to know how
to interpret graphs like the one shown in Figure 1. This figure is
a *line graph*. Line graphs

#### 2 Rates of Change

Change is at the heart of physics. That’s because physics is the science that seeks to explain why anything happens at all! The physicist wants to know what makes any given situation develop as time progresses. In order to begin to answer this question, it is important to be able to understand change, and rates of change, intuitively as well as quantitatively...

#### 5 Position and Velocity, Revisited

Chapter 3 introduced a few basic ideas about position and velocity: • An object’s position vector **r** tells how far from the origin the object is and in what direction. • To draw the position vector, start with the tail at the origin and end with the tip at the location of the object.
• An object’s velocity vector **v** tells how fast the object is moving and in what direction...

#### 6 Introducing Acceleration

The word *acceleration* means something different in physics than it does in everyday speech. In everyday speech, *acceleration* means only “speeding up.” But in physics, speeding up is just *one* of the meanings of the word *acceleration*. Strangely enough, in physics *acceleration* can also mean slowing down! In common speech, slowing down is sometimes...

#### 7 Acceleration as a Rate of Change

Imagine cruising along in your car with a constant, unchanging velocity vector **v**. Your car is just humming along, following a straight, flat road, maintaining a constant speed. Bored by the monotony, at risk of falling asleep at the wheel, you decide that you want to *change* your velocity vector. What are some ways you
could do it...

#### 8 Focus on a-Perp

As the concept map in Chapter 7 (Figure 108) illustrates, there are two basic ways to view the acceleration vector. • As we discussed in Chapter 6, we can view the acceleration vector as an indication of whether an object is speeding up, slowing down, or turning. • Equally well, as we discussed...

#### 9 Case Study: Straight-Line Motion

Sometimes there are simple situations in which the motion of an object is confined more or less to a straight line. Think of driving a car along a straight (and flat) road, stepping off of a diving board and falling straight down, working a yo-yo straight up and down, or riding on an escalator...

#### 11 Combining Forces That Act on the Same Target

At any given time, your body is subject to a number of noticeable influences. The earth pulls you down. Your chair pushes you up. The moon and sun tug on you slightly, the other celestial bodies negligibly so. Now a breeze ruffles your hair; the air is exerting a force on you as well. All of these forces can be combined, leading to a single net influence. This net...

#### 12 “Newton‘s Little Law”

Congratulations! You’ve reached the very threshold of the System of the World. Already you have journeyed across a varied landscape of physics. You have studied rates of change, and also rates of change of rates of change. You have added and subtracted vectors. You have examined...

#### 13 Newton’s Second Law

“What is mass?” is a profound question. Indeed, modern physical theories such as field theory and string theory are still trying to sort this out. In this book we’ll take the commonsense view Newton himself took: Mass is simply the amount of “material stuff” contained in an object...

#### 14 Dynamics

Newton’s Second Law permits us to solve two basic kinds of problems.
These problems are in a sense the reverse of one another: • *Problem Type 1*. By observing the motion of an object, deduce the nature of the forces at work on it. • *Problem Type 2*. By knowing something about the forces at work on an object, predict its...

#### 15 Newton’s Third Law

In Chapter 10 I explained that every action is an *inter*action. You
can’t touch without *being* touched. Newton’s Third Law formalizes
this idea and makes it quantitative. Here it is:
*Newton’s Third Law*: If object 1 exerts a force on object 2,
object 2 must also exert an equal and opposite force on object...

#### 16 Kinds of Force

Every force has a *type*, or *kind*. For example, the force that the
sun exerts on the earth is of the gravitational kind. The force that
a magnet exerts on a nail is of the magnetic kind. The force
that lifts your hairs after you rub a balloon on your head is of
the electrostatic kind. Table 5 lists...

E-ISBN-13: 9780801896323

E-ISBN-10: 0801896320

Print-ISBN-13: 9780801891601

Print-ISBN-10: 0801891604

Page Count: 440

Illustrations: 3 halftones, 349 line drawings

Publication Year: 2009

OCLC Number: 647865474

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