Answer
As a wave passes, the motion of a floating object can be described in several ways.
First, the vertical motion of the object is affected by the wave's crest and trough. As the wave crest passes beneath the object, it experiences an upward buoyant force, causing it to rise. Conversely, the object encounters a downward force as the wave trough passes, causing it to descend. This vertical displacement is known as heave motion.
Second, the horizontal motion of the object is influenced by the wave's orbital motion. Water particles move in a circular or elliptical path as the wave progresses. This orbital motion imparts a lateral force on the floating object, causing it to move back and forth in the direction of wave propagation. This horizontal displacement is referred to as sway motion.
Finally, there is also a rotational motion called pitch that can occur. As the wave passes, the changing water surface can induce a rocking motion of the floating object around its longitudinal axis. This rotation is known as pitch motion.
Work Step by Step
From the text of section 20.2
