Two events occur simultaneously on the x axis of reference frame S,one at x =+a and the other at x = +a. According to an observer moving in the positive x direction:
A) the event at x = +a occurs first
B) the event x =+a occurs first
C) either event might occur first, depending on the value of a and the observer's speed
D) the events are simultaneous
E) none of the above

Question

Quizplus · Accepted Answer

In the observer's frame moving in the positive x direction, events that are simultaneous in one frame are not simultaneous in another due to the relativity of simultaneity. The event at x = +a occurs first because it is in the direction of the observer's motion.

Two Events Occur Simultaneously on the X Axis of Reference