**Java Security Update:** Oracle has updated the security settings needed to run Physlets.

Click here for help on updating Java and setting Java security.

# Chapter 2: Space and Time in Special Relativity

Special relativity, along with quantum mechanics, is considered a cornerstone of modern physics. In fact, the combination of special relativity and quantum mechanics yields relativistic quantum mechanics. While this book is not a book on relativistic quantum mechanics,^{1} the knowledge of basic relativity is important for the understanding of quantum mechanics.

# Table of Contents

## Sections

- Section 2.1: Synchronizing Clocks.
- Section 2.2: Exploring Synchronizing Clocks by Viewing.
- Section 2.3: Simultaneity.
- Section 2.4: Light Clocks, Time Dilation, and Length Contraction.
- Section 2.5: Understanding Spacetime Diagrams.
- Section 2.6: Exploring Worldlines by Matching.
- Section 2.7: Exploring the Pole and Barn Paradox.
- Section 2.8: Exploring the Twin Paradox.

## Problems

- Problem 2.1: Which of these is not an inertial reference frame?
- Problem 2.2: Who emitted the signal first?
- Problem 2.3: A spaceship flies close to a space beacon at 70% of c.
- Problem 2.4: A pole vaulter carries her pole towards a red barn.
- Problem 2.5: Draw the spacetime diagram.
- Problem 2.6: With what speed must the triangle travel to be isosceles?
- Problem 2.7: Which of the following is true for all relative velocities?

^{1}See for example, J. J. Sakurai, *Advanced Quantum Mechanics*, Addison-Wesley (1967).