Two sound waves (speed 343 m/s) have different wavelengths. The first has a wavelength of 5.72 m, and the second a wavelength of 11.44 m. What beat frequency do you hear from these two waves?

The beat frequency is 30 Hz

Explanation:

Given;

velocity of the two sound waves, v = 343 m/s

wavelength of the first wave, λ₁ = 5.72 m

wavelength of the second wave, λ₂ = 11.44 m

The frequency of the first wave is calculated as follows;

F₁ = v/λ₁

F₁ = 343 / 5.72

F₁ = 59.97 HZ

The frequency of the second wave is calculated as follows;

F₂ = v/λ₂

F₂ = 343 / 11.44

F₂ = 29.98 Hz

The beat frequency is calculated as;

Fb = F₁ - F₂

Fb =  59.97 HZ - 29.98 Hz

Fb = 30 Hz

i am pretty sure it is c because when people are closer together, they cannot move as freely. picture being in a mostly full elevator, for instance. the people are right next to you, and you can barely move.