Oscillations are defined as the process of repeating vibrations of any quantity about its equilibrium position. The word “oscillation” originates from the Latin verb, which means to swing. An object oscillates whenever a force pushes or pulls it back toward its central point after displacement. This force could be described as a restoring force because it essentially aims at pushing the object back to its equilibrium or central position. The working of the restoring force makes the object oscillate around its equilibrium position.
In this article, we will learn about, Oscillation definition, Oscillation Motion, Types of Oscillations, Examples of Oscillations, and others in detail.
What is Oscillation?
Oscillation of an object is the back-and-forth movement between two positions or states. It is sometimes also called the repetitive motion that keeps on repeating in a recurring cycle. For instance, a sine wave with side-to-side pendulum movement or the up and down motion by weight on springs. The movement that is taking place around an equilibrium point or a mean value. This motion is also called the periodic motion. One oscillation is a completed movement over some time either side-to-side or up down.
The motion of a body is considered an oscillatory or vibration if it moves from to and fro about a certain point after some definite period. The mean position or equilibrium position, the point about which the body oscillates is referred to as a fixed point. All oscillatory movements are periodical but every periodic movement is not an oscillating one. Some of the instances in oscillatory motion include vibrations of sitar-wire and mass suspension from spring.
A very important example of oscillation motion is the Simple Pendulum. Now first let's learn about it.
Simple Pendulum
A pendulum is a mechanical setup that shows an oscillatory motion. The simple pendulum is a small bob of mass 'm' suspended by a thin string attached to the free end at an upper edge with length L along its platform. The image of a simple pendulum is added below,
A simple pendulum period can be made longer by elongating the string and taking measurements from the point of suspension to the middle part between two points which is on a bob. However, it should be emphasized that when the mass of the bob is modified, the period will not vary. This is because the strength of the gravitational field is not constant everywhere, and hence this period depends primarily on the pendulum’s position from Earth.
Oscillation Motion
Oscillatory motion is the back-and-forth movement of an object from a central place or equilibrium. Such movement is usually referred to as oscillations or cycles, and this particular idea forms a basis of learning physics and also engineering. A typical motion is characterized by a periodic pattern, which sees the object in question away from its equilibrium position where it reaches at maximum displacement before returning to equilibrium and moving on to the opposite extreme.
Oscillation of Wave
Oscillation is a back and forth motion of an object between two points of deformation. Oscillation in any medium creates a wave, which is a disturbance that propagates from where it was created in all possible direction.
Amplitude of Oscillation
Amplitude of oscillation is the maximum distance traveled from its mean position. It is the distance between two crest or two troughs.
Oscillation Types
Various types of oscilations are,
- Damped Oscillations
- Undamped Oscillations
- Free Oscillation
- Resonance
- Coupled Oscillation
Damped Oscillation
A damped oscillation refers to any form of the vibrational process that results in a diminishing amplitude with each ensuing cycle. The complementary of a damped oscillation is an undamped one that has the same amplitude during all of the oscillations. There are two types of damped oscillations: underdamped and overdamped. In an underdamped system, the amplitude of the oscillations decays but it never drops to zero. In an overdamped oscillation, the amplitude of these waves drops down until it reaches zero. There are many possible causes of damping, which may include the friction or aerodynamic drag. Damping is a negative process since it means the loss of energy. But in certain instances, damping can be applied to either control or stabilize an oscillating system.
Graph of damped oscillation is added below,
Different Types of Damped Oscillations
Various types of damped oscillations are,
- Under Damped Oscillations
- Critically Damped Oscillations
- Overdamped Oscillations
Under Damped Oscillations
Underdamping oscillation is a type of the damped system which after some time returns back to its own equilibrium position but with very small amplitudes. That is, the force damping applied to such a system does not have enough strength that would rapidly accelerate it quickly into rest.
Behavior of the motion in an underdamped system shows a very typical trend. The change in the position of the oscillating object from its resting point obeys a sinusoidal or an exponential decay function. Each subsequent oscillation becomes less and the system takes a lot of time to return completely at rest.
Critically Damped Oscillation
In the critically damped oscillation, the system does not cede any energy. In such an oscillation, the damping is precisely proportional to the displacement precluding any overshoot or undershoot. The system tends to the equilibrium in the shortest possible time with no oscillations. Unlike an underdamped system that does not return to the equilibrium as rapidly and continues in oscillatory mode around the steady state point, this is a critically damped system. Critically damped systems are widely used in various engineering applications requiring a quick return to the equilibrium and also minimal vibrations.
Overdamped Oscillations
Overdamped oscillation refers to the damping whereby the amplitudes of the oscillations approach the equilibrium point gradually and do not create any ring around this state. In the case of overdamped oscillations, the damping constant is greater than one. The energy dissipation in an overdamped oscillating system is more larger compared to the other modes of damping.
In the condition of overdamped oscillations, more damping is provided than necessary to bring about rest or equilibrium point and therefore it takes a large amount of time as compared with other methods. Under this mechanism, no further shuttling movement will take place beyond the equilibrium point.
Undamped Oscillations
The undamped oscillation describes a periodic motion, where being displaced in the point of equilibrium causes restoring force proportional to its position. Therefore, in the undamped system—the oscillation never disappears and its magnitude stays at a constant value. Alternating current (AC wave) is an example of an undamped oscillation.
Alternating current varies between two values across the neutral position and it repeats with no change in magnitude or the time period. The amplitude of the signal does not change which is a time, and there is no hindering force in the alternating currents.
Free Oscillation
A free oscillation occurs when the system vibrates or has an oscillatory motion caused by forces intrinsic to that particular system and which is not disturbed from external actions. The natural frequency of the system refers to free vibration.
A case in point of free oscillation is a pendulum moving left and right once its displacement from equilibrium has been initiated. Had air resistance or friction been non-existent, the pendulum would have swung back and forth without end at its frequency of resonance.
Resonance
Resonance is a phenomenon that takes place when an external force or frequency applied to the system coincides with its own natural frequency. This leads to a substantial growth in the amplitude of the oscillations. Resonance causes vibrations and boosting is an essential process in many disciplines, including physics and engineering but also music too.
Coupled Oscillation
With regard to coupled oscillation, it means that there is more than one system or an oscillator which interact with each other. The movement of one system can affect the other and vice versa, resulting to a coupled or linked behaviour. This coupling may involve the physical links or energy transfer between the oscillators.
Some of the oscillation formulas are,
Oscillation Period Formula
Time period in oscillation is calculated using the formula,
T = 2π √L/g
where,
- L is Length of Pendulum
- g is Acceleration due to Gravity
Frequency Formula Oscillation
Frequency is the inverse of time period and is calculated by the formula,
f = 1/T
where,
- f is Frequency of Oscillation
- T is Time Period of Oscillation
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Examples of Oscillations
Oscillation is the most common phenomenon in nature such as the tides of sea and for a simple pendulum motion underlying clock. The other form of vibration is the spring's motion.
- String vibrations in guitars and in any other string instruments can also be regarded as the oscillation.
- As the pendulum swings back and forth, it generates an oscillatory motion. Mechanical oscillations are called vibrations. A vibrated particle implies that it oscillates between the two positions around its point of equilibrium.
- Spring motion is also an example of oscillation. This spring moves backward and forwards alternatively, producing a vibrating motion.
- Sine wave is also an example of oscillation. This is a wave that moves between the two points around the centre.
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Frequently Asked Questions on Oscillations
What is Meant by Oscillation?
The back and forth motion of any object between two positions or states is called the oscillation.
What is Free Oscillation?
When the body vibrates at its dynamic frequency without any external influence, it is called free oscillation.
What are Forced Oscillations?
If the oscillation of a body is due to an external force then it’s called forced vibrations.
What is Oscillatory Motion?
A repeating motion where the object oscillates around its equilibrium position by a restoring force or torque
What is Damping Force?
The damping force is the resistance-producing force.