Simultaneity: A rocket is moving at 1/4 the speed of light relative to Earth. At the center of this rocket, a light suddenly flashes. To an observer at rest in the rocket,
A) the light will reach the front of the rocket at the same instant that it reaches the back of the rocket.
B) the light will reach the front of the rocket before it reaches the back of the rocket.
C) the light will reach the front of the rocket after it reaches the back of the rocket.

Question

Quizplus · Accepted Answer

This is because to an observer at rest in the rocket, the distance between the front and back of the rocket is fixed. Therefore, since the light travels at a constant speed in all directions relative to the observer, it will reach the front and back of the rocket at the same time. This is in accordance with the principle of simultaneity, which states that events that are simultaneous in one frame of reference are also simultaneous in all frames of reference moving at a constant velocity relative to that frame.

Simultaneity: a Rocket Is Moving at 1/4 the Speed of Light