Question

a cyclist completes semi circle of a radius 120m in 1m find average speed and average velocity

Answer 1

distance = 2(pi)r/2 = (pi)r = 120(pi)
time taken = 1 min. = 60 s
         av. speed = distance/time taken =120(pi)/60 = 2(pi) m/s = 6.28 m/s

displacement=final point - initial point =diameter=2(radius)=2(120)=240
time taken = 1 min = 60s
        av velocity = displacement/time taken = 240/60 = 4 m/s