Imagine you are a member of a team of young engineers working on a project of autonomous robots. Your team has recently built a small robot named "Rover" that can independently explore rooms. One day, while testing Rover's capabilities in the school hall, the robot suddenly disappears from your sight. Rover is programmed to move at a constant speed and can only change direction when it encounters an obstacle. The last time you saw it, it was moving straight towards the north wall of the hall at a speed of 0.5 meters per second. The hall is 20 meters long.