15. Two loudspeakers are placed 6.0 m apart. They produce the same sounds, in step, across a frequency range of 1908 Hz to 2471 Hz Point P is located 4.70 m from one loudspeaker and 3.60 m from the other. What frequency of sound from the two speakers will produce constructive interference at point P? Assume the speed of sound is
314 m/s

2420 Hz
2110 Hz
2340 Hz
2190 HZ
2220 Hz

At a certain instant after jumping from the airplane a, a skydiver b is in the position shown and has reached a terminal (constant) speed vb = 52 m/s. the airplane has the same constant speed va = 52 m/s, and after a period of level flight is just beginning to follow the circular path shown of radius ρa = 2330 m. (a) determine the velocity and acceleration of the airplane relative to the skydiver. (b) determine the time rate of change of the speed vr of the airplane and the radius of curvature ρr of its path, both as observed by the nonrotating skydiver.