Question

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. What is the magnitude of the displacement vector for each? For which girl is this equal to the actual length of path skate?

Answer 1

displacement depends on position only so the magnitude of displacement is the distance between intial and final point in this case distance between P and Q which is diameter of circle 2×radius

2×200m=400m

since initial point and final point are same in all cases so magnitude of displacement for each girl in 400m

now girl B has same magnitude of displacement and distance

Answer 2

Explanation:

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Displacement is given by the minimum distance between the initial and final position of particle

In the given case, all the girls start from point P and reach point Q. The magnitudes of their displacements will be equal to the diameter of the ground

Radius of the ground = 200m

Diameter of the ground = 200 * 2 = 400m

Hence, the magnitude of the displacement for each girl is 400m. This is equal to the actual path skated by girl B