(Originais Teachy 2024) - Question Easy of Physics

When designing a new soundtrack for a virtual reality game, a group of developers wants to create an immersive auditory experience that explores the phenomena of sound beating. To achieve this, they plan to use two sound sources that emit frequencies that, when overlapped, create a beating pattern that they want to impress the players with. The frequency of the first source is 440 Hz, corresponding to an A note, and the frequency of the second source needs to be chosen in a way that the resulting beating has a frequency of 4 Hz. Considering that the beating is perceived as the regular variation of sound intensity and that the speed of sound in the air is approximately 343 m/s, what should be the frequency of the second sound source to meet the developers' specifications?