Question

justify why every simple harmonic motion is a periodic motion whereas the converse need not be true in tidal waves and waves on pond surface​

Answer 1

Answer:

The motion that repeats itself at regular intervals of time is called periodic motion. If the periodic motion is (1) linear and (2) the acceleration of the particle executing the motion is proportional to its displacement from the position of equilibrium and is always directed towards the mean position, only then the motion of the particle is said to be simple harmonic. The motion of the hands of a clock or the motion of the planets and satellites are periodic in nature. But as these motions do not satisfy the above conditions, they cannot be called simple harmonic. So it can be said that all simple harmonic motions are periodic but all periodic motions are not simple harmonic.