Two automobiles are equipped with the same singlefrequency horn. when one is at rest and the other is moving toward the first at 17 m/s , the driver at rest hears a beat frequency of 9.0 hz .

Zamir and talia raced through a maze. zamir walked 2 m north, 2 m east, 4 m south, 2 m east, 4 m north, 2 m east, 3 m south, 4 m east and 4 m north. talia walked 2 m north, 6 m east, 3 m south, 4 m east, and 4 m north. compare their displacements: zamir's displacement is talia's displacement.