Answered

Turbo was heartbroken and so upset that he stood on the beach to relax. It turned out that the tsunami (dol wave) had a wavelength of 20 kilometers. If Turbo saw 2 waves within 5 seconds, at what speed would Turbo have to run in kilometers per second to survive?
1. 5 kilometers per second
2. 8 kilometers per second
3. 12 kilometers per second
4. 15 kilometers per second
5. 18 kilometers per second



Answer :

Answer:

2. 8 kilometers per second

Explanation:

We can find the speed Turbo have to run by using this formula:

[tex]\boxed{v=\lambda f}[/tex]

where:

  • [tex]v=\texttt{speed of wave}[/tex]
  • [tex]\lambda=\texttt{wavelength}[/tex]
  • [tex]f=\texttt{frequency}[/tex]

Frequency means the total number of wave per 1 second. Since Turbo saw 2 waves in 5 seconds, then the number of wave in 1 second (frequency):

[tex]\displaystyle f=2\ waves\div 5\ seconds[/tex]

[tex]\displaystyle\bf f=\frac{2}{5} \ Hz[/tex]

Given λ = 20 km, then the speed:

[tex]\begin{aligned}v&=\lambda f\\&=20\times\frac{2}{5} \\&=\bf 8\ km/s\end{aligned}[/tex]