1. \quad \text{파동 속력: } v = \sqrt{\dfrac{T}{\mu}} = \sqrt{\dfrac{40.0}{0.0050}} \approx 89.44\ \text{m/s} \text{ 입니다.}

2. \quad \text{세 번째 배진동: } f_3 = 3\dfrac{v}{2L} = 3\dfrac{89.44\ \text{m/s}}{2(0.50\ \text{m})} \approx 268.3\ \text{Hz} \text{ 입니다.}