How much displacement occurs when completing one round of circular play-ground $7\,m$ radius?
A. $0\,m$
B. $7\,m$
C. $22\,m$
D. $18\,m$

Hint: In order to answer this question, to know the displacement occurring when completing one round of circular play-ground $7\,m$ radius, we will go through the concept of displacement to solve this question.

Complete step by step answer:
Suppose any object is completing one complete round of a circular play-ground of radius $7\,m$.
Radius, $r = 7\,m$
So, the displacement is $0\,m$, because after completing the complete one-ground of a circular play-ground, the object again reaches its initial point.

And, we can also understand this question according to the explanation of displacement. The displacement is a vector quantity that is affected by both the location and the direction.When the body returns to its original location in a circular motion, the displacement of the body is the shortest distance between the final and initial positions of the object. As a result, there is no displacement or the displacement is zero.

Hence, the correct option is A.

Note:We should know the difference between the displacement and the magnitude of displacement, if in the question, they asked for the magnitude of displacement, then we should find the total distance covered by the object to complete one-round of the playground as we know magnitude is some quantity always.