When a piano tuner strikes both the A above middle C on the piano and a 440 Hz tuning fork, he hears 4 beats each second. The frequency of the piano's:. A) 444 Hz
B) 880 Hz
C) 436 Hz
D) either 436 Hz or 444 Hz

D) either 436 Hz or 444 Hz

Explanation:

frequency of the tuning fork, F₁ =  440 Hz

frequency of the piano, F₂ = ?

Beat frequency, F = 4 Hz

Beat frequency is given as the difference between the frequency of the two instruments  and it is given by;

F = F₂ - F₁                    or        F =  F₁ - F₂

F₂ = F + F₁                   or        F - F₁ = - F₂

F₂ = 4 Hz + 440 Hz    or       4 - 440 = - F₂

F₂ = 444 Hz                or      - 436 = - F₂

F₂ = 444 Hz               or         F₂ = 436 Hz

Therefore, the frequency of the piano is 444 Hz or 436 Hz

50 inches should be the resultant vector

the answer is 3.1 his answer is wrong mines is right