A runner in a relay race runs 20m north, turns around and runs south for 30 m, then turns north again and runs 40m. the entire run took 30 seconds. what was the average speed of the runner? what was the average velocity of the runner?

Answer 1

total distance covered: 20+30+40=90m
total time: 30s
avg speed: 90/30 = 3m/s

final displacement: 20-30+40=30m north
avg speed: 30/30 = 1 m/s north