Step-by-step explanation:
6.
displacement only measures the direct distance between a start and an end point.
distance measures the lengths of all movements from the start to the end point.
600 meters to the school and 600 meters back means that Jay traveled a distance of 600 + 600 = 1200 meters.
but because the start point = the end point, the displacement at the end of the journey is 0 meters.
7.
8 laps of 400 meters each.
that means she ran 8×400 = 3200 meters.
7a.
16 minutes are 16×60 = 960 seconds.
so,
16 minutes and 20 seconds = 960 + 20 = 980 seconds.
7b.
her average speed was
3200 meters / 980 seconds = 3200/980 m/s = 160/49 m/s = 3.265306122... m/s