Summary

• Optical resolution
• Galilean relativity

• Written Quiz    Timer
  
  
  
• Einstein's postulates
  1. Galileo was right
  2. The speed of light
     Example #1
  
  
• Consequence #1: simultaneity
  
  Example #2
  
  
  
  

gc6 26.q5
If you were on a spaceship traveling at 0.5c away from a star, at what speed would that star's light pass you?
A. 1.5c                B. 1.0c
C. 0.67c              D. 0.5c
Answer







kw5 10.
Mary stands on the ground and observes that as a train passes her, simultaneous flashes occur in the engine and the caboose. What would Ed say if he is riding on the train?
A. The engine flashed first.
B. The flashes are simultaneous.
C. The caboose flashed first.
Answer







 



B. 1.0c
The speed of light is independent of the inertial FOR, so an observer in the ship would measure a speed of 1.0c. If he didn't, he would know that he is moving, and the star would comprise an absolute reference frame for the universe.













 



A. The engine flashed first.
Mary argues that Ed only thinks the engine flashed first because he is moving toward that signal and away from the caboose signal. Ed argues that Mary only thinks the flashes are simultaneous because she is moving toward the caboose signal and away from the engine signal. The dispute cannot be settled unless one of them enters the FOR of the other.