Insight: compare the distance between the Earth and Alpha Centauri as measured by the Earth Observer and the Astronaut in the spaceship, which one is the proper length, which one is the contracted length? How do they fit into the respective definitions? No submission.

Part D $-$ The length of the spaceship as measured by the Earth observer is $50\mathrm{.}0$ m$.$ What is the length of the spaceship measured by the Astronaut on the spaceship?

Keep $2$ digits after the decimal point. Unit is meter.

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length of spaceship measured by Astronaut on spaceship $=$

nothing

m