Damped and forced oscillations, resonance
Cambridge A-Level Physics (9702) · Unit 17: Oscillations · 8 flashcards
Damped and forced oscillations, resonance is topic 17.3 in the Cambridge A-Level Physics (9702) syllabus , positioned in Unit 17 — Oscillations , alongside Simple harmonic oscillations and Energy in simple harmonic motion. In one line: Damping is the process by which energy is dissipated from an oscillating system, causing the amplitude of oscillations to decrease over time. This is typically due to resistive forces like friction or air resistance.
Marked as A2 Level: examined at A Level in Paper 4 (A Level Structured Questions) and Paper 5 (Planning, Analysis and Evaluation). It is not tested on the AS-only papers (Papers 1, 2 and 3).
The deck below contains 8 flashcards — 3 definitions and 5 key concepts — covering the precise wording mark schemes reward. Use the 3 definition cards to lock down command-word answers (define, state), then move on to the concept and calculation cards to handle explain, describe, calculate and compare questions.
Damping in the context of oscillations
Damping is the process by which energy is dissipated from an oscillating system, causing the amplitude of oscillations to decrease over time. This is typically due to resistive forces like friction or air resistance.
What the Cambridge 9702 syllabus says
Official 2025-2027 spec · A2 LevelThese are the exact learning outcomes Cambridge sets for this topic. The candidate is expected to be able to do each of these on the relevant paper.
- understand that a resistive force acting on an oscillating system causes damping
- understand and use the terms light, critical and heavy damping and sketch displacement–time graphs illustrating these types of damping
- understand that resonance involves a maximum amplitude of oscillations and that this occurs when an oscillating system is forced to oscillate at its natural frequency
Cambridge syllabus keywords to use in your answers
These are the official Cambridge 9702 terms tagged to this section. Mark schemes credit responses that use the exact term — weave them into your answers verbatim rather than paraphrasing.
Tips to avoid common mistakes in Damped and forced oscillations, resonance
- › Explicitly state that the minus sign shows acceleration is always in the opposite direction to displacement and directed towards the equilibrium position.
- › Provide the continuation of oscillations as the primary evidence for light damping.
What is damping in the context of oscillations?
Damping is the process by which energy is dissipated from an oscillating system, causing the amplitude of oscillations to decrease over time. This is typically due to resistive forces like friction or air resistance.
Describe light damping and its effect on oscillation amplitude.
Light damping causes the amplitude of oscillations to decrease gradually over time. The system oscillates many times before coming to rest, exhibiting an exponential decay in amplitude.
What is critical damping and why is it significant?
Critical damping is the damping condition where the oscillating system returns to equilibrium as quickly as possible without oscillating. It's significant because it represents the fastest return to equilibrium.
Explain the characteristics of heavy damping (overdamping).
Heavy damping (overdamping) causes the system to return to equilibrium very slowly, without oscillating. It takes longer to reach equilibrium compared to critical damping.
Sketch a displacement-time graph for a heavily damped oscillator.
The graph should show the displacement gradually returning to zero without any oscillations. It should approach zero asymptotically and take significantly longer to settle than critical damping.
Define forced oscillation and its relationship to resonance.
A forced oscillation occurs when an external periodic force is applied to an oscillating system. Resonance occurs when the driving frequency of the external force matches the system's natural frequency, resulting in a maximum amplitude of oscillation.
Explain the conditions necessary for resonance to occur.
Resonance happens when the driving frequency of an external force matches the natural frequency of the oscillating system. At resonance, the amplitude of the oscillations is at its maximum. Minimal damping is required for clear resonance.
How does damping affect the sharpness of resonance?
Increased damping reduces the amplitude at resonance and broadens the resonance curve. A lower Q-factor broadens the resonance peak.
Review the material
Read full revision notes on Damped and forced oscillations, resonance — definitions, equations, common mistakes, and exam tips.
Read NotesMore topics in Unit 17 — Oscillations
Damped and forced oscillations, resonance sits alongside these A-Level Physics decks in the same syllabus unit. Each uses the same spaced-repetition system, so progress in one informs the next.
Key terms covered in this Damped and forced oscillations, resonance deck
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