What does position 3 tell us?

- At 50 seconds, the particle is back where it started with respect to its north-south coordinates. The slope of the line is -2, so it is moving to the south at a velocity of 2 m/s. It has traveled a total distance of 40 meters: 20 meters north and 20 meters south. The particle's total displacement is zero, assuming that it is not moving east or west.