In oscillatory motion, an object tends to repeat certain movements in the same pattern repeatedly until it is acted upon by some external force. The movement of an oscillating object can be to and fro, back and forth, or vibratory in nature. In the absence of friction, the oscillatory motion has the ability to go on forever till eternity. For example, a pendulum, flapping of bird wings, etc.
Examples of Oscillatory Motion
1. Pendulum Clock
A pendulum clock is one of the perfect examples of oscillatory motion. This is because the pendulum of the clock gets displaced from its original position, and it returns back after covering a certain distance on both sides of the normal position. This to and fro movement of the pendulum bob goes on and on.
2. Tuning Fork
When a tuning fork is struck against the glass, it tends to vibrate rapidly. The vibration of the tuning fork is yet another example of oscillatory motion because the tines of the tuning fork move a particular distance on either side of the equilibrium position.
A swing is one of the prominent examples of oscillatory motion in real life. Initially, when the swing is in the rest state, it is said to be in equilibrium. When a push force is applied to the swing, the equilibrium gets disrupted, and the swing gets displaced in a direction. After covering a certain distance, it returns to the original position, and it covers an equal distance in the opposite direction, thereby exhibiting oscillatory motion.
4. Flapping of Wings
Insects and birds fly by flapping their wings repeatedly and periodically. The wings tend to move a particular distance above the original position, return to the equilibrium position, move the same distance in the opposite direction, move back to the original position, and so on. This rhythmic motion of their wings is nothing but an example of oscillatory motion.
5. A freely hanging Bob
When a freely hanging bob is pushed, it tends to change its position from equilibrium by moving a certain distance on one side, returning again to the equilibrium, then moving the same distance on the other side. This process goes on and on till the energy dies out. Hence, a bob freely hanging with the help of a string exhibits oscillatory motion in the best possible manner.
6. String Musical Instruments
A number of stringed musical instruments such as a guitar, violin, cello, harp, etc., display the oscillatory or vibratory motion in real life. This is because when the string of such musical instruments is pulled or pushed, it gets displaced from its original position and covers an equal magnitude of distance on either side of the rest position.
7. Spring Toy
When a spring toy is stretched and released, it tends to move back and forth repeatedly. When the spring toy gets expanded, it moves towards one side covering a certain distance. It then returns to its original position and covers the equal distance in the opposite direction, i.e., it gets compressed. The spring repeats this motion periodically for some time. This motion is nothing but an oscillatory motion.
8. Alternating Current
The waveform of an alternating current is a sinusoidal waveform. Hence, the oscillatory motion of ac or the alternating current can be observed clearly. The crest and the troughs of the signal demonstrate the maximum displacement of the physical quantity in either direction, while the axis signifies its equilibrium position.
9. Beating of Heart
Our heartbeat is constant and rhythmic in nature. When our heart pumps the blood in and out, it causes the heart muscles to move to and fro. This motion of the muscles away from the normal position in opposite directions indicates the existence of oscillatory motion.
The motion of tectonic plates of the earth during an earthquake is yet another example of oscillatory motion. This is because the plates vibrate to and fro along with a central or mean position. The magnitude of the distance covered on either side of the equilibrium position remains the same, thereby displaying oscillatory motion.