A Foron cruiser moving directly toward a Reptulian scout ship fires a decoy toward the scout ship. Relative to the scout ship, the speed of the decoy is 0.980c and the speed of the Foron cruiser is 0.900c.What is the speed of the decoy relative to the cruiser?

Electromagnetic radiation from a star is observed with an earth-based telescope. The star is moving away from the earth with a speed of 0.590c. If the radiation has a frequency of 8.64 x 10 Hz in the rest frame of the star, what is the frequency measured by an observer on earth? a) Of = 4.39 x 1014 Hz b) Of = 4.93 x 1014HZ c)Of = 4.45 x 1014 Hz d) Of = 4.39 x 1015 Hz e) Of = 4.69 x 1014 Hz

The nearest star to Earth is Proxima Centauri, which is 4.3 light years away. The spacecraft Potemkin is sent to this star at a constant velocity of 0.73c, and the craft carries a light beacon that flashes once a day to signal the earth that all is well. While traveling to the star the Potemkin passes a similar ship returning from the star at the same speed. How long does the trip take according to the space travelers inside the Potemkin? (b) (a) How long does the trip take according to Earth observers? (c) According to the space travelers inside the Potemkin, what is the distance to Proxima Centauri? (d) What is the speed of the returning craft as seen from the Potemkin What is the rate at which flashes are seen on Earth from the Potemkin? (e) (f) What is the rate of flashes sent by the returning craft as seen by the Earth observers?

How far from the earth would you be able to travel in a lifetime of 88 years if you were able to travel at a constant speed of 0.67c?