Three girls skating on a circular ice ground of radius 200 m start from a point P on the edge of the ground and reach a point Q diametrically opposite to P following different paths as shown in Fig. 4.20. What is the magnitude of the displacement vector for each? For which girl is this equal to the actual length of path skate ?
Displacement of an object is given by the change in its position. Here, the initial position is P and the final position is Q for all three girls. So, the displacement is same for all the three girls and its magnitude is equal to the diameter of the circular ice ground.
So, Magnitude of Displacement = 2×Radius = 2×200m=400m
The magnitude of the displacement is equal to the actual path length travelled for girl B since she moved along the diameter.