Answer :
Explanation
We are required to determine the speed at which the tsunami that started with an earthquake in Sumatra struck Sri Lanka about 1550 km away.
The formula given is:
[tex]\begin{gathered} v=\sqrt{gh} \\ where \\ g=acceleration\text{ due to gravity} \\ h=depth\text{ of the ocean } \end{gathered}[/tex]Therefore, we have:
[tex]\begin{gathered} v=\sqrt{gh} \\ where \\ g=9.8\text{ m/s}^2 \\ h=4000m \\ \\ \therefore v=\sqrt{9.8\times4000} \\ v\approx198\text{ m/s} \end{gathered}[/tex]Hence, the answer is:
[tex]v\approx198\text{ m/s}[/tex]