Advanced physics

2. A spaceship and its crew bound for a planet in the 1|vlega system leave Earth at speed (33" 5):; when both its clock and the clock on Earth read t = F]. Twenty weeks later, according to the earth clock, Earthlings realize that there may he an imposter aboard the ship, so they immediately translate a radio message at v = c towards the ship, informing the ship of their suspicions. Upon receiving the message, the ship's computer immediately discovers the imposter lurking in one of the vents, so the crew instantly [and safely] eject the imposter at speed (aware) relative to the ship back towards Earth, returning the imposter to stand trial. [a] How many weeks does it take the signal to reach the spaceship? [b] How fast is the imposter traveling relative to earth? {c} How long does it take the imposter to return to Earth? How long was he in space