Why does the change in momentum occur over the time taken to travel distance 2L?
Answers
Due to kinetic Energy ^-^
Kinetic Energy is simply the result of it’s mass times it’s velocity. There is no accounting for time or distance. So unless some event were to occur to alter the velocity or the mass of the object, that object would have the exact same Kinetic Energy at day one, as it would have at day infinite.
Now if you are traveling at relativistic speeds, and viewing from multiple reference points, the distance it traveled may be different from one reference point to another, which means it’s velocity would be different and then it’s Kinetic Energy would also be different. this however is 100% a product of inertial reference frames, and nothing to do with the actual distance traveled. If you make the measurements from within the same frame of reference, there will be no change.