| a-t graph | Varying Acceleration |
| about | Editorial |
| absolute zero | Thermal Expansion |
| absorption | Absorption |
| | Interaction of Light with Matter |
| accelerating spacecrafts | The slingshot effect |
| acceleration | Homework Problems |
| | Accelerating a cart |
| | Newton’s Second Law |
| | An accelerating bus |
| | Positive and Negative Acceleration |
| | Varying Acceleration |
| | Summary - Acceleration |
| | The Acceleration Vector |
| acceleration vector | Summary - Vectors and Motion |
| addition of vectors | Order of addition |
| Albert Einstein | Albert Einstein |
| alpha decay | The Strong Nuclear Force, Alpha Decay and Fission |
| | The Weak Nuclear Force; Beta Decay |
| alpha radiation | Radioactivity |
| amplitude | Period, Frequency, and Amplitude |
| angular momentum | Introduction to Angular Momentum |
| | Conservation of Angular Momentum |
| | Restriction to rotation in a plane |
| | Angular Momentum in Planetary Motion |
| | Two Theorems About Angular Momentum |
| | Torque: the Rate of Transfer of Angular Momentum |
| | Summary - Angular Momentum |
| | Angular Momentum in Three Dimensions |
| | Summary - Atom |
| | Discussion - Angular Momentum |
| antenna | Wavelength of radio waves |
| antineutrino | The Weak Nuclear Force; Beta Decay |
| area | Scaling of Area and Volume |
| | Scaling of Irregular Objects |
| Aristotle | The Motion of Falling Objects |
| ATLAS accelerator | ATLAS accelerator |
| | Superconductors |
| atom | The discovery of the neutron |
| | Direct proof that atoms existed |
| atom model | The Planetary Model of the Atom |
| atom nucleus | Sizes and shapes of nuclei |
| atomism | Atomism |
| average | Applications of Calculus |
| average lifetime | Average lifetime |
| Avogadro's number | Pressure, volume, and temperature |
