Solution:When a simple pendulum immersed in water then its oscillations are damped and its wave is cosine wave.
Oscillation
When a body is in periodic motion such that it moves in a to and fro motion about a fixed point, then it is said to be in oscillation and the motion associated with this is called oscillatory motion. One cycle of to and fro motion is termed as one oscillation.
The maximum distance traveled by the body from its mean position is called the amplitude of oscillation. Time taken by the body to complete one oscillation is called the time period. The number of cycles completed in one second is called frequency of oscillation.
Motion of a simple pendulum, motion of spring block system, motion of a mass along the diameter of earth, motion of swing in the park are some examples of oscillatory motion.