Chapter 11, Problem 67GP

To determine

To Find: The time in which people have to run to safety.

Answer to Problem 67GP

The people have $20$ minutes to run to safety.

Explanation of Solution

Given Information:

Wavelength of tsunami, $\lambda =250\text{km}=250\times {10}^3\text{m}$

Velocity of tsunami, $v=750\text{km/h}=208.3\text{m/s}$

Concept used:

  $t=\frac{\lambda }{v}$

Here, $\lambda$ is the wavelength and v is the velocity.

Calculation:

  $t=\frac{\lambda }{v}$

  $\begin{array}{l}t=\frac{250\times {10}^3\text{m}}{208.3\text{m/s}}\\ t=1200\text{s}\\ t=20\min \end{array}$

Conclusion:

The people have $20$ minutes to run to safety.