Question

One of a pair of 28-year-old twins takes a round trip through space while the other twin remains on Earth. The traveling twin moves at a speed of 0.92c for a total of 40 years, according to Earth time.

Part A Assuming that special relativity applies for the entire trip (that is, neglect accelerations at the start, end, and turnaround), what are the twins' ages when the traveling twin returns to Earth?

Earth twin's age, travelling twin's age =

Part B

On the trip, how far from Earth did the traveling twin go according to the traveling twin?

Part C

On the trip, how far from Earth did the traveling twin go according to the Earth twin?

Part D

Which of your answers to parts B and C are proper lengths, if any?

Which of your answers to parts B and C are proper lengths, if any?

distance as measured by the traveling twin

distance as measured by the Earth twin

none of them

Answer 1

D) answer to part B is the proper length as it is measured in rest frame that is the distance measured by the traveling twin .

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