In the distant future, a physics 360 student is rushing to her exam traveling in a spaceship at relativistic speed. She passes a policeman at rest a distance 9 km from a traffic signal (measured in his rest frame).
a) The policeman monitors the student's tail lights (red light with ? = 650 nm in her rest frame) with a spectroscope, viewing directly along her motion away from him. He observes a wavelength ?=1300nm (infrared). What is her speed relative to the policeman?
b) How long, according to her, does it take to reach the traffic signal?
c) When the policeman stops her for running a red light she claims that she saw the traffic signal as green (i.e., ¸ = 520 nm). Compute the wavelength she would have seen. Is she telling the truth?