Question

Two small boats are $10\text{m}$ apart on a lake. Each pops up and down with a period of $4.0\text{seconds}$ due to wave motion on the surface of water. When one boat is at its highest point, the other boat is at its lowest point. Both boats are always within a single cycle of the waves. The speed of the waves is (in m/s)

Answer 1

Time period of the wave $\left(T\right)=4\text{s}$
$\lambda =2\times$ distance between boats.
$\lambda =2\times 10$
$\lambda =20\text{m}$
Speed of the wave $\left(V\right)=\frac{\lambda }{T}$
$=\frac{20}{4}=5\text{m/s}$