Starting at the beginning and have been having some difficulty explaining the implications of the constancy of the speed of light. Seeking confirmation that I at least have it right. For all scenarios below the observer is Bob standing in the middle of a train car moving at speed v. Bob has a pull cord connected mechanically to each end of the train car such that when he pulls the cord the time to trigger an event at each end of the train car is identical - Scenario 1) Bob’s cord is attached to guns pointed at his head. He pulls the chords and after identical response times the guns fire . Speed of bullet from the back end of the car is v(b) + v, speed of bullet from the front end of the car is v(b) – v. Bullets hit Bob, who is moving at speed v with the train car, at the same time. - Scenario 2) Bob’s cord is attached to a mallet that hits a gong when pulled. He pulls the cord and after identical response times the gongs sound. Speed of sound from back of train is v(s) +v, speed of sound from front of train is v(s) – v. Sound reaches Bob, who is moving at speed v with the train, at the same time. - Scenario 3) Bob’s cord is attached to flashlights pointed at him. He pulls the cord and after identical response times the flashlights turn on. Speed of light from the back of train is c and speed of light from front of train is c. Bob, moving at speed v with the train car sees the light from the front of the car first. Is this the gist of it?