Serway & Jewett — Superposition and Standing Waves: Problem 42

Two speakers are driven by the same oscillator of frequency \( f \). They are located a distance \( d \) from each other on a vertical pole. A man walks straight toward the lower speaker in a direction perpendicular to the pole as shown in Figure P17.42. (a) How many times will he hear a minimum in sound intensity? (b) How far is he from the pole at these moments? Let \( v \) represent the speed of sound and assume that the ground does not reflect sound. The man’s ears are at the same level as the lower speaker.