A runner, jogging along a straight line path, starts at a position 60 m east of a milestone marker and heads west. After a short time interval he is20 m west of the mile marker. Choose east to be the positive x -direction.
(a) What is the runner's displacement from his starting point?
(b) What is his displacement from the milestone?
(c) The runner then turns around and heads east. If at a later time the runner is 140 m east of the milestone, what is his displacement from the starting point at this time?
(d) What is the total distance traveled from the starting point if the runner stops at the final position listed in part (c)?