Question
A cyclist starts from the center O of circle of park of radius 1 km, reaches the edge P of the park, then cycles along the circumference to point Q and returns to the centre along QO as shown. If the round trip takes 10 minutes, then what is:

(a) net displacement
(b) average velocity
(c) average speed of the cyclist?
Solution
(a) The cyclist starts from O and again returns to point O. Therefore, the initial and the final point are the same. Hence, displacement of cyclist is equal to zero.
(b) Average velocity of cyclist is zero because total displacement of cyclist is zero.
(c) Total distance travelled by cyclist is,
∴ Average speed =
Here, we have
Radius of the circle park,
and
Time taken for round trip,
∴