Answer:
D I think I might be wrong its been a while scense I did something like that
Answer:
0.786 Hz, 1.572 Hz, 2.358 Hz, 3.144 Hz
Explanation:
The fundamental frequency of a standing wave on a string is given by

where
L is the length of the string
T is the tension in the string
is the mass per unit length
For the string in the problem,
L = 30.0 m

T = 20.0 N
Substituting into the equation, we find the fundamental frequency:

The next frequencies (harmonics) are given by

with n being an integer number and f being the fundamental frequency.
So we get:



A mechanical wave<span> is a </span>wave<span> that is an oscillation of </span>matter<span>, and therefore transfers energy through a </span>medium.[1]<span> While waves can move over long distances, the movement of the </span>medium of transmission<span>—the material—is limited. Therefore, oscillating material does not move far from its initial equilibrium position. Mechanical waves transport energy. This energy propagates in the same direction as the wave. Any kind of wave (mechanical or electromagnetic) has a certain energy. Mechanical waves can be produced only in media which possess elasticity and inertia.</span>