Tsunamis A tsunami is a tidal wave caused by an earthquake beneath the sea. These waves ca...

Tsunamis A tsunami is a tidal wave caused by an earthquake beneath the sea. These waves can be more than 100 feet in height and can travel at great speeds. Engineers sometimes represent such waves by trigonometric expressions of the form y = a cos bt and use these representations to estimate the effectiveness of sea walls. Suppose that a wave has height h = 50 ft and period 30 minutes and is traveling at the rate of 180 ft/sec.

EXERCISE

(a) Let (x, y) be a point on the wave represented in the figure. Express y as a function of t if y = 25 ft when t = 0.

(b) The wave length L is the distance between two successive crests of the wave. Approximate L in feet.