A water wave traveling in a straight line on a lake is described by the equation.
y(x, t) = 3.75cm cos (0.450 cm−1x + 5.40s−1t)
where y is the displacement perpendicular to the undisturbed surface of the lake. How much time does it take for one complete wave pattern to go past a fisherman in a boat at anchor?
on comparing the equation to
y = A sin (kx± ωt+ϕ)
We get ω = 5.40 s−1
The time required for one complete wave to go part the fisherman, since the fisherman is at rest, is one time period.
T=2πω=2×3.145.4=1.16 s
A full wave takes 1.16 s to go past the fisherman.