Introduction - Frames of reference

Unit 4: Special Relativity Frames of Reference

Page 1: Introduction

• Unit Overview: Focuses on special relativity and the concept of frames of reference.

Page 2: Motion Perception

• Observer's Perspective:

  • Questions whether an observer (e.g., a person or object) is at rest or moving at a high speed relative to the sun.

Page 3: Learning Objectives

• Key Terms to Define:

  • Frame of Reference: A coordinate system used to measure the position and motion of objects.

  • Inertial Frame of Reference: A frame that is not accelerating.

• Key Concept: Motion can only be measured relative to an observer.

Page 4: Key Definitions

• Classical Mechanics:

  • Study of motion governed by Newton's Laws, also called Newtonian physics.

• Relativistic Effect:

  • Occurs when time and space differ for one object compared to another due to relative motion.

Page 5: Relative Motion

• Galileo's Experiment:

  • If a sailor drops an object from the top of a moving mast (constant velocity), questions arise about where it will land and how its motion will be perceived by different observers.

Page 6: Frame of Reference

• Definition:

  • Framework for describing motion with respect to a coordinate system.

• Types of Frames:

  • Inertial: Non-accelerating reference frames.

  • Non-inertial: Accelerating reference frames.

Page 7: Example Frames of Reference

• Situations Analyzed:

  • Ground and vehicle scenarios, e.g., a car, a plane, or stationary observers.

• Understanding Relative Velocities:

  • Different speeds provided (e.g., 50 m/s, 300 m/s) illustrate relative motion.

Page 8: Check Your Understanding: Stationary Car

• Question: From which frame(s) does the car appear stationary?

  • Options: A. Standing on roadsideB. Car going opposite direction at same speedC. Inside the carD. Airplane overheadE. Same speed in the same direction

Page 9: Check Your Understanding: Ball on Train

• Task: Illustrate the path of a ball thrown and caught while:

  • a) Observer on the train

  • b) Observer on the platform at the station

Page 10: Inertial vs Non-inertial Frames

• Inertia Definition: Resistance to change in motion.

• Inertial Frame of Reference:

  • Not accelerating: can be stationary or moving with constant velocity.

  • Newton’s 1st Law and other physics laws apply.

• Non-Inertial Frame of Reference:

  • Accelerating, where conditions change significantly.

  • Examples:

    • Inertial: Train moving at constant speed; standing at a train station.

    • Non-inertial: Plane accelerating on the runway; car turning a corner at constant speed.