16.9 Waves  (Page 2/8)

Calculate the velocity of wave propagation: gull in the ocean

Calculate the wave velocity of the ocean wave in [link] if the distance between wave crests is 10.0 m and the time for a sea gull to bob up and down is 5.00 s.

Strategy

We are asked to find $v_{\text{w}}$ . The given information tells us that $\lambda =\text{10}\text{.}0\text{m}$ and $T=5\text{.}\text{00}\text{s}$ . Therefore, we can use $v_{\text{w}}=\frac{\lambda }{T}$ to find the wave velocity.

Solution

1. Enter the known values into $v_{\text{w}}=\frac{\lambda }{T}$ :
   $v_{\text{w}}=\frac{\text{10.0 m}}{5\text{.00 s}}.$
2. Solve for $v_{\text{w}}$ to find $v_{\text{w}}\text{= 2.00 m/s.}$

Discussion

This slow speed seems reasonable for an ocean wave. Note that the wave moves to the right in the figure at this speed, not the varying speed at which the sea gull moves up and down.