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
Explanation:
Assuming that all forces extend from the origin point, with
and
lying in the xy plane, so
is along the z axis. So, we have:

The net force is:

The force (
) that would exactly counterbalance these three forces will be opposite in direction and equal in magnitude to the net force:

Answer:
Correct answer: Ek = I² / 2 · m
Explanation:
The formula by which kinetic energy is calculated is:
Ek = m V² / 2
The formula by which momentum i prefer the name impulse is calculated is:
I = m V
We will transform the formula for kinetic energy on the next way:
Ek = m V² / 2 we will multiply numerator and denominator with m and get:
Ek = m² V² / 2 m = (m v)² / 2 m = I² / 2 m
Ek = I² / 2 m
God is with you!!!