A spaceship visits Alpha Centauri and returns to Earth. Alpha ...

[awywial]

A spaceship visits Alpha Centauri and returns to Earth. Alpha Centauri is 4.5 light-years from Earth (our second closest star).
 
  If the spaceship travels at one-half the speed of light for essentially all of its expedition, how long was the ship gone according to an observer on the spaceship?

Question 2

What is the minimum distance of two points on the moon that can be just resolved by the Keck 10. meter telescope in Hawaii (use a wavelength of 600. nm, lunar distance of 380. thousand Km):
 
  (a) if there were no atmosphere?
  (b) if the atmosphere limits resolution to 0.2 arc-sec?

[meganlapinski]

Answer to Question 1

7.8 years

Answer to Question 2

(a) 28. meters
(b) 0.4 Km

[awywial]

Thanks

[meganlapinski]

Welcome