1. Two loudspeakers are placed at either end of a gymnasium, both pointing toward the center of the gym and equidistant from it. The speakers emit 296 Hz sound that is in phase. An observer at the center of the gym experiences constructive interference. How far toward either speaker must the observer walk to first experience destructive interference? 2. A pair of in-phase stereo speakers is placed side by side, 0.894 m apart. You stand directly in front of one of the speakers, 2.34 m from the speaker. What is the lowest frequency that will produce constructive interference at your location? 3. A popular car stereo has four speakers, each rated at 60 W. In answering the following questions, assume that the speakers produce sound at their maximum power. The threshold of hearing is defined as the minimum discernible intensity of the sound. It is approximately 10-12 W/m^2. Find the distance d from the car at which the sound from the stereo can still be discerned. Assume that the windows are rolled down and that each speaker actually produces 0.06 W of sound, as suggested in the last follow-up comment. 4. Pulses A, B, C, and D all travel at 10 m/s on the same string but in opposite directions. The string is depicted at time t = 0 in the figure. The small pulses have an amplitude of 2.0 cm, and the large pulse has an amplitude of 4.0 cm. Find the displacement of point P at time t = 0.10 s. Find the displacement of point P at time t = 0.20 s Figure: