An observer O is standing on a platform of length L = 90 m on a station. A rocket train passes at a relative (constant) speed of 0.96c moving parallel to the edge of the platform. Then, the observer O found that the front and back of the rocket train simultaneously line up with the ends of the plat form at a particular instant.
(a) In the rest frame of the observer O, what is the time necessary for the rocket train to pass a particular point on the platform?
(b) What is the rest length L_0 of the rocket train?
(c) According to another observer O′ on the rocket train, what is the length L′ of the platform?
(d) Again, according to observer O′ on the rocket train, how long does it take for observer O to pass the entire length of the rocket train?