An astronaut travels to a distant star with a speed of 0.56 c relative to Earth. From the astronaut's point of view, the star is 7.6 ly from Earth. On the return trip, the astronaut travels with a speed of 0.88 c relative to Earth. What is the distance covered on the return trip, as measured by the astronaut? Give your answer in light-years.

When a vertical beam of light passes through a transparent medium, the rate at which its intensity i decreases is proportional to i(t), where t represents the thickness of the medium (in feet). in clear seawater, the intensity 3 feet below the surface is 25% of the initial intensity i0 of the incident beam. what is the intensity of the beam "10" feet below the surface? (give your answer in terms of i0. round any constants or coefficients to five decimal places.)