What is Periodic Motion? Examples of Periodic Motion
If a moving object repeats its motion in a fixed interval of time, the motion of such an object is called periodic motion.
Example: The motion of the planets around the sun, the motion of a pendulum, the vibration of an elastic spring all are some examples of periodic motion.
Types of Periodic Motion:
We can divide the periodic motion into several types. They are –
1. Circular periodic motion: If the motion of an object repeats along a circular path at a given time, then the motion of that object is called circular periodic motion. For example, when an object is tied to a thread and rotated at a certain speed, the object follows a circular path. Such motion is a circular periodic motion.
2. Linear periodic motion: If an object completes a periodic motion along a straight line at a given time, then we can call the motion of that object a linear periodic motion. For example, the piston in the engine cylinder of a motor vehicle moves along a linear path. So the speed of the piston inside the cylinder of a motor vehicle engine is the linear periodic speed. That’s why it is an example of linear periodic motion.
3. Vibrational periodic motion: If a vibrating particle repeats its motion over in a fixed interval of time, then such motion is called vibrational periodic motion.
What is Oscillatory Motion? – Examples of Oscillatory Motion
Oscillatory Motions: If an object with periodic motion is to and fro on the same path about a fixed position, then the motion of that object is called oscillation.
Examples: (a) When a simple pendulum is slightly pulled and released, it completes a periodic motion along a certain path. So, we can call it an oscillatory motion.
(b) When a stretched wire is pulled in the middle and released, it vibrates on both sides of the equilibrium. This type of motion is also known as oscillatory motion.
Frequently Asked Questions about Periodic Motion and Oscillatory Motion – FAQs
All oscillatory motions are periodic, but not all periodic motions are oscillatory in nature. The vibrating body must possess to and fro motion about its mean position for oscillatory motion.
Example: Uniform circular motion is periodic but not oscillatory motion.
(a) When a heavy object is hung on an elastic spring and released, the vibrates along a particular path. This is an example of oscillatory motion.
(b) When a stretched wire is pulled in the middle and released, it vibrates on both sides of the equilibrium. This type of motion is also known as oscillatory motion.
What are the properties of Oscillatory Motion?
1. Time period (T): Time taken by a vibrating object to complete one oscillation is known as the time period. It is denoted by T.
2. Frequency (f): The number of oscillations completed by a vibrating particle in one second is known as the frequency of the vibrating body. It is denoted by f. The S.I. unit of frequency is ‘Hertz’ or ‘cycles per second.’
3. Amplitude (A): The maximum displacement of a vibrating body from its equilibrium position is called the amplitude of the vibrating body.
4. Phase (ϕ): A physical quantity that expresses an oscillating particle’s position and direction of motion is called phase.