Answer
87 N
Work Step by Step
Use equation 11-19b for a vibrating string, and equation 11–13 for the speed of a wave on a string.
$$f_1=\frac{v}{2 \mathcal{l}}=\frac{1}{2 \mathcal{l}}\sqrt{\frac{F_T}{m/\mathcal{l}}}$$
Using a length of 0.32 m, f = 440 Hz, and a mass of 0.00035 kg, solve for a tension force of 87 N.
