Moving objects can actually be shorter, given the barn yard paradox. Whats the difference between perceived and real length?
They are indeed really shorter. The perceived and real lengths are the same. We will see more later about how this can be consistent with the “barn yard paradox”; this is actually in your homework set, cast in the form of a pole vaulter problem. The scheme for measuring proper length that you presented is somewhat confusing because the two events (moving observer passing one end of ruler, moving observer passing right end of ruler) are not simultaneous in either observer’s frame. Generally, when I want to measure the proper length between two events, I go to a frame in which those two events are simultaneous. A better scheme would be to have the stationary observer place synchronized time-bombs at each end of the rule, then measure the time difference between arrival of the wavefronts from the two explosions. There is no need to use simultaneous events in order to determine the relation between measured and proper length. (Note that “proper length between two events” does not have
Related Questions
- For objects moving away but not directly away in our light of sight, could we take measurements from different parts of the Earth and compare the readings to figure out precise velocity?
- What guidance is available around choice of care setting/care home given the economical difference in costs associated to both when the PCT is responsible for funding?
- In thin-film interference, what does phase difference actually mean?
