The discussion centers on the concept that both velocity and kinetic energy are frame variant, meaning they depend on the observer's frame of reference. Participants emphasize that energy cannot be considered objective due to its variability across different frames, a principle established in both Newtonian physics and relativity. The terms "frame variant" and "invariant" are highlighted as more accurate descriptors than "subjective" and "objective." The inability to identify a privileged frame of reference is a long-standing conclusion in physics, supported by both Galileo and Einstein.
PREREQUISITESPhysics students, educators, and anyone interested in the foundational concepts of mechanics and relativity will benefit from this discussion.
The usual terms are "frame variant" instead of "subjective" and "invariant" instead of "objective". Energy is frame variant, this is not due to relativity, it is frame variant in Newtonian physics also.zeromodz said:If velocity is subjective to an observers frame of reference, then isn't energy (kinetic) also subjective? How can we define energy as objective if it changes depending on your frame of reference?