Explanation:
Average velocity is displacement over time.
Average speed is distance over time.
a) In the first half of the race, the displacement is 50m, and the distance is also 50m.
v = 50m / 20s = 2.5 m/s
s = 50m / 20s = 2.5 m/s
b) In the second half of the race, the displacement is -50m. The distance is 50m.
v = -50m / 22s = -2.27 m/s
s = 50m / 22s = 2.27 m/s
c) In the total trip, the displacement is 0m. The distance is 100m.
v = 0m / 42s = 0 m/s
s = 100m / 42s = 2.38 m/s
