일반물리학 1 — Waves-II: Problem 39

39 A violin string 30.0 cm long with linear density 0.650 g/m is placed near a loudspeaker that is fed by an audio oscillator of variable frequency. It is found that the string is set into oscillation only at the frequencies 1040 and 1560 Hz as the frequency of the oscillator is varied over the range 600–1600 Hz. What is the tension in the string?