Periodic Motion is the Motion which which repeats itself after a fixed interval of time.
For Example - A Swing in the Garden or A pendulum of a clock because they repeat their movement after a fixed time.

Periodic motion refers to the motion of an object that repeats itself after a regular interval of time. It is a type of motion that occurs in a predictable pattern or cycle. Many natural phenomena and man-made objects exhibit periodic motion, such as the swinging of a pendulum, the rotation of the Earth around its axis, the oscillation of a spring, and the vibration of a guitar string.

Characteristics of periodic motion:
Periodic motion possesses the following characteristics:

1. Period: The period is the time it takes for one complete cycle of motion to occur. It is represented by the symbol 'T'. For example, in the case of a pendulum, the period is the time required for the pendulum to swing from one extreme position to the other and back again.

2. Frequency: Frequency is the number of complete cycles of motion that occur in one second. It is represented by the symbol 'f' and is the reciprocal of the period. The unit of frequency is Hertz (Hz). For example, if the period of a motion is 2 seconds, the frequency would be 0.5 Hz (1/2).

3. Amplitude: The amplitude of periodic motion is the maximum displacement or distance from the equilibrium position. It represents the magnitude or intensity of the motion. In the case of a pendulum, the amplitude is the maximum angle reached by the pendulum bob.

4. Equilibrium position: The equilibrium position is the central or rest position around which the object oscillates. It is the position where the net force acting on the object is zero.

Examples of periodic motion:
1. Swinging pendulum: A pendulum swings back and forth in a regular pattern, with each swing taking the same amount of time. The motion of a pendulum is periodic.

2. Vibrating guitar string: When a guitar string is plucked or strummed, it vibrates and produces sound. The vibrations of the guitar string are periodic.

3. Rotating Earth: The Earth rotates on its axis, completing one full rotation in approximately 24 hours. This rotation is periodic and gives rise to day and night.

4. Oscillating spring: When a spring is stretched or compressed and then released, it undergoes periodic motion as it oscillates back and forth around its equilibrium position.

5. Heartbeat: The contraction and relaxation of the heart muscles follow a periodic pattern, resulting in the heartbeat.

In conclusion, periodic motion refers to the regular and repetitive motion of an object that occurs in a predictable pattern or cycle. It is characterized by its period, frequency, amplitude, and equilibrium position. Various natural phenomena and man-made objects exhibit periodic motion, making it a fundamental concept in the study of motion and measurement of distances.