We will have the following:
First, we remember:
[tex]\lambda=\frac{v}{f}[/tex]Then we will have:
[tex]\left(8.4m\right?)=\frac{\left(449.4m/s\right)}{f}\Rightarrow f=\frac{\left(449.4m/s\right)}{\left(8.4m\right)}[/tex][tex]\Rightarrow f=53.5Hz[/tex]So, the frequency of the wave is 53.5 Hz.
