Total distance covered by Usha in 1 min.is 180 m.
Displacement of Usha in 1 min = 0 m
Average speed `= ("Total distance covered")/("Total time taken")`
`=(180 m)/(1 "min")=(180 m)/(1 "min")xx(1 "min")/(60 s)`
Average velocity` =
("Displacement")/("Total time taken")`
`= (0m)/(60 s)`
`= 0 m s^(–1)`
The average speed of Usha is 3 m `s^(-1)` and her average velocity is 0 m `s^(-1)`.