Question

Part one: Alpha Centauri is not only the closest star system to us (it is actually a triple star system) but it also seems to be an excellent place to look for extraterrestrial life. It is about 4.3 light years away from Earth. If an astronaut claims her journey there and back only took 6.3 years, then how fast was she traveling? (Assume she made a fast turnaround once she arrived there!) A. 0.68c B. 0.73c C. 0.86c D. 0.81c E. 0.54c

Part Two: The Sun radiates electromagnetic energy at the rate of 3.92 × 1026 W. The mass of the Sun is 1.99 × 1030 kg. What fraction of the Sun’s mass is lost during a human lifetime of 75 years? A. 2.16 × 10–13 B. 1.42 × 10–14 C. 6.90 × 10–14 D. 5.18 × 10–12 E. 8.63 × 10

Answer 1

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