A runner covers a straight 600 m stretch from point A to point B at a constant speed of 8.0 m\,s−1. Without stopping, he immediately turns around and returns the same 600 m from B back to A at a constant speed of 12.0 m\,s−1.
(i) Calculate the time taken for each leg of the journey.
(ii) Determine the runner’s average speed for the complete out–and–back trip.
(iii) Determine his average velocity for the complete trip.