A moving object’s length in a given frame is defined to be the distance between two events that occur at oppo­site ends of the object and that are simultaneous in that frame. Why is it crucial that the events we use to define a moving object’s length be simultaneous?

A. This is purely conventional: there is no other reason.
B. This choice makes it easier to use the Lorentz transfor­mation equations to find the length.
C. If the events are not constrained to be simultaneous, then the length is poorly defined: its value would depend on the time interval between the events.
D. If the events are simultaneous, then the length will be a frame-independent quantity.
E. Other (specify)


C. If the events are not constrained to be simultaneous, then the length is poorly defined: its value would depend on the time interval between the events.

Physics & Space Science

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