- Free oscillations
- Motion of an Oscillator
What are oscillations?
To-&-fro motion between 2 limits.
What is a single oscillation?
One complete movement from starting/rest position, to the maximum displacement in both directions, then back to the starting position.
Oscillations can be divided into certain categories & subcategories:
- Free oscillations (see below)
- Simple Harmonic Motion (see here)
- Damped oscillations (see here)
- Forced oscillations (see here)
Let’s look at Free Oscillations first.
What is a free oscillation?
The oscillation of a system with no externally applied stimuli.
It oscillates with:
- Constant amplitude
- Constant total energy (no energy lost)
What is an oscillator?
A mechanical or electronic device that works on the principles of oscillation (periodic fluctuation between 2 positions based on changes in energy).
An oscillator utilising simple harmonic oscillation is a harmonic oscillator.
- Metal detectors
Motion in Free Oscillation
In real life, most oscillations do NOT oscillate freely (there is usually some loss of energy).
However, some can be approximated to have free oscillations & simple harmonic motion.
We will look at 2 examples:
- a pendulum (with an angle less than 10°)
- a vertical weighted spring (where extension does not exceed proportionality limit)
& see how their motion can be represented.
|Mapped onto a Circle|
Components of free oscillation
|Aspect||Definition||Denoted by:||In Free Oscillation:|
|Displacement||Vector distance of a particle from its equilibrium position||x
Measured in cm or m
|Varies with time|
|Amplitude||Maximum displacement from rest position||x0
Measured in cm or m
|Period||Time taken for one complete oscillation||T
Measured in s
|Frequency||Number of oscillations in one second||f = 1/T
Measured in Hz
|Angular Frequency||Angular displacement (in radian) per unit time
This angle is the angle travelled when an oscillation is MAPPED onto a CIRCLE
|ω = 2πf
Measured in rad s-1
|Phase Difference||Difference in time or angle of oscillation between 2 identical oscillating objects||φ
Measured in s OR °
⇐ Previous in Physics:
⇐ Previous in A2 Physics:
⇒ Next in Physics: Simple Harmonic Motion