What is a free vibration?
An oscillation after a system is displaced from equilibrium and released, without a continuing periodic driving force.
AQA A-level Physics (7408) · 3.6.1.4
Revise AQA A-level Physics (7408) specification point 3.6.1.4, Forced vibrations and resonance (A-level only), with free active-recall flashcards. Flip through the set or review every question and answer below.
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What is a free vibration?
An oscillation after a system is displaced from equilibrium and released, without a continuing periodic driving force.
What causes a displaced and released system to oscillate freely?
A restoring influence.
For weak damping, how does the frequency of a free vibration relate to the system’s natural frequency?
It is approximately equal to the natural frequency.
What determines a system’s natural frequency?
Its physical properties.
How does damping affect the amplitude of a free vibration?
Damping transfers energy away from the oscillation, causing its amplitude to decrease with time.
What happens to the amplitude of an ideal free vibration without damping?
It remains constant.
What are forced vibrations?
Oscillations produced by a periodic external driving force.
How can a driver maintain vibrations despite damping?
It transfers energy to the system, compensating for energy dissipated by damping.
At what frequency does a damped, driven system vibrate after transient motion has died away?
At the frequency of the driving force.
What determines the amplitude of a steady forced vibration?
The driving conditions and the properties of the system.