Book contents
- Frontmatter
- Contents
- Preface to English edition
- Preface to Japanese edition
- Part I Kinematics: Relativity without any equations
- 1 Welcome to the world of relativity
- 2 Basics
- 3 Galilean relativity
- 4 Einsteinian relativity
- 5 Causality
- 6 Consequences
- 7 Summary of Part I
- Part II Problems
- Part III Dynamics: Relativity with a few equations
- Afterword
- References
- Index
2 - Basics
Published online by Cambridge University Press: 05 June 2012
- Frontmatter
- Contents
- Preface to English edition
- Preface to Japanese edition
- Part I Kinematics: Relativity without any equations
- 1 Welcome to the world of relativity
- 2 Basics
- 3 Galilean relativity
- 4 Einsteinian relativity
- 5 Causality
- 6 Consequences
- 7 Summary of Part I
- Part II Problems
- Part III Dynamics: Relativity with a few equations
- Afterword
- References
- Index
Summary
Questions about motion
When studying the motion of an object, the most basic questions we would like to ask are things like:
Q1: Is it moving or is it at rest (not moving)?
Q2: If it is moving, what is its direction of motion?
Q3: What is its speed in that direction?
In order to answer these questions, we need to know the object's location in space at each instant in time, so that we can keep track of how it is changing as time progresses. If we find that the object's location in space is not changing with time, that is, if it stays at the same place, then we can say that it is “at rest,” while otherwise we can say that it is “moving.” If the object is “moving,” we can specify its direction of motion by saying things like “it is moving to the left” or “it is moving to the right,” and we can figure out its speed by determining by how much its location in space is changing per unit time.
Once we have these basic questions under control, we can then start to ask more advanced questions like:
Q4: Is the direction of motion changing with time?
Q5: Is the speed changing with time?
Q6: If they are changing, what is causing it?
- Type
- Chapter
- Information
- An Illustrated Guide to Relativity , pp. 4 - 29Publisher: Cambridge University PressPrint publication year: 2010