A beat is an interference pattern between two sounds of slightly different frequencies, perceived as a periodic variation in volume whose rate is the difference of the two frequencies. Frequency beat is equal to,

The reference frequency in our case would be 392Hz, and since there is the possibility of the upper and lower range for the amount of beats per second that the two possible frequencies are heard would be


Therefore the two possible frequencies the piano wire is vibrating at, would be 396Hz and 388Hz
I think the answer for the question above its b 1.2
When A Light Ray Hits A Boundary,,,,, it is called refraction.
Answer:
72.1 m
Explanation:
Hello!
When the walker walks west, each block he walks will be of 100 m, so the walker walked 4*100m = 400 m west.
Similarly, when the walker walks south, he walks 20 meters per block, therefore, the walker walked 4*20 m = 80 m south.
Since the directions west and south are perpendicular, the distance between the start ad end point is:
d = √(400^2 + 80^2) m = 407.92 m
However the walker traveled 480 m
Therefore, the walker traveled 480 - 407.9 m = 72.1 m farther than the actual distance