A boy moves along a circular path of perimeter 30 m and comes back to the point where he started the journey, the displacement of the boy is
A boy is moving along a circular track in anticlockwise sense. A point sound source moves along a regular hexagonal path. The centres of hexagonal track and the circular track coincide as shown in the figure. The source and boy starts from point B and A respectively such that P, A & B always lie on the same radial line. At what point, the frequency heard by the boy is minimum?