The velocity of a wave is described by the following equation:
[tex]v= \lambda f[/tex]
Where v is velocity, λ is the wavelength and f is the frequency. Note that the wavelength given is: [tex]13mm=13 \times 10^{-3}m[/tex]
Thus,
[tex]v=(13 \times 10^{-3}m)(4Hz)=0.052m/s=5.2 \times 10^{-2}m/s=5.2cm/s[/tex]
The velocity is 5.2 cm/second or 0.052 m/s or 52 mm/s
