Question

Alice G LOO Bob Let's revisit the simultaneity problem from worksheet 11. To make things concrete, we'll include specific numbers. Bob is standing on the ground watching Alice go by in a high-speed train. As seen in Bob's reference frame, Alice is traveling to the right at speed v = +0.80c. As measured in Bob's frame, Alice's rail car is 12 m long. Alice is sitting in the exact center of the train car. At the instant that the Alice passes Bob, two flash bulbs at either end of the train flash simultaneously, each emitting a pulse of light toward Alice. As measured in Bob's frame, the coordinates of the left flash are XL= -6.0 m, tu = 0 s, and the coordinates of the right flash are XR = +6.0 m, tr = 0 s. a) What is Alice's Lorentz factory, as measured by Bob? b) Use the Lorentz transformation to calculate the coordinates of the two flashes, (x',t') and (x'Rit'R), in Alice's reference frame. c) In Bob's frame, three things happen simultaneously at t = 0: (1) Alice passes Bob; (2) the left bulb flashes; and (3) the right bulb flashes. Are these events simultaneous in Alice's frame? If not, what is the order of these events in Alice's' frame? d) Are your answers in part c consistent with the conclusions you reached for problem 4 in worksheet 11? Explain why or why not. e) Who measures the proper length of the rail car: Alice, Bob, or neither?

Answer 1

postulate #1 from relativity: the speed of light is finite and same for all inertial observers. Simultaneily is a relative concept. It it is simultaneous in one reforesance frame, the in another reference frome in relative notion it is not simultaneous (a) If the bulb flashes simultaneously for Alice the the flashes assine at her limultaneously, since she is stationary relative to the train. (6) From Bob's perpertine since right she will intercept sight first, then from the Alice is moning the flash from left side! te < 2074" (exe) ! you have * Please any let me know if questions.