Amicrophone is located on the line connecting two speakers that are 0.513 m apart and oscillating in phase. the microphone is 1.80 m from the midpoint of the two speakers. what are the lowest two frequencies that produce an interference maximum at the microphone's location?

The experiment done in lab is repeated, using a ball that has unknown mass m. you plot your data in the form of f 2 versus m/l, with f in rev/s, m in kg, and l in m. your data falls close to a straight line that has slope 3.19 m/(kg · s2). use g = 9.80 m/s2 and calculate the mass m of the ball.