An astronaut travels to a star system 4.5 ly away at a speed of 0.90c. Assume that the time needed to accelerate and accelerate is negligible.
a. How long does the journey lake according to Mission Control on earth?
b. How long does the journey take according to the astronaut?
c. How much time elapses between the launch and the arrival of the first radio message from the astronaut saying that she has arrived?
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College Physics: A Strategic Approach (3rd Edition)
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