Final answer:
The fundamental frequency of the vibrating cord is approximately 14.18 Hz.
Step-by-step explanation:
To determine the fundamental frequency of the vibrating cord, we can use the equation for the fundamental frequency of a vibrating string:
f1 = 1/2L * sqrt(T / μ)
Where f1 is the fundamental frequency, L is the total length of the cord, T is the tension in the cord, and μ is the linear density of the cord.
Plugging in the given values, we have: f1 = 1/2 * 7.00 * sqrt(90 / 0.007)
Simplifying this equation gives us the fundamental frequency of the cord: f1 ≈ 14.18 Hz