Question

a body travels along a circular path of radius 70m.after travelling half a revolution in 20 s,find (i) average velocity and (ii) average speed.

Answer 1

avg velocity =total displacement / total time
                   = (70 + 70) / 20
                   =140/20
                   =7m/s
avg speed = total distance / total time
                  =  πr/20
                  =220/20     (220 is approx value)
                  =11m/s

Answer 2

distance covered by body = d = 2πr/2 = πr = 22/7×70 = 22×10 = 220m

displacement of the body = D = diameter = 2r = 2×70 = 140 m

average velocity = displacement/time = 140/20 = 7m/s

average speed = distance/time = 220/20 = 11m/s