Circular Motion and Simple Harmonic Motion
Analysing angular motion, centripetal acceleration and force, simple harmonic motion, energy exchange, damping and driven oscillations.
How to study A-level Physics
Define the system, represent the physics, select a justified model, calculate transparently, then test the result against units, limits and evidence.
Core concepts
Concept 1
Uniform circular motion has acceleration toward the centre even when speed is constant.
Exam cue: Identify the real forces whose resultant supplies centripetal acceleration.
Concept 2
Simple harmonic motion has acceleration proportional to displacement and opposite in direction.
Exam cue: Choose a consistent equilibrium origin and sign convention for SHM.
Concept 3
Kinetic and potential energy exchange through an ideal oscillation; damping dissipates energy and changes resonance.
Exam cue: Use the phase relationship among displacement, velocity and acceleration.
Risk pitfalls and guardrails
Adding a separate 'centripetal force' to the real forces.
Guardrail: Do not substitute a memorised formula until you have identified the system, variables, direction, assumptions and valid range of the model.
Confusing angular frequency with ordinary frequency.
Guardrail: Do not substitute a memorised formula until you have identified the system, variables, direction, assumptions and valid range of the model.
Assuming every periodic motion is simple harmonic.
Guardrail: Do not substitute a memorised formula until you have identified the system, variables, direction, assumptions and valid range of the model.
Memory anchors
Centripetal Acceleration
Centripetal acceleration points toward the centre and equals speed squared divided by radius.
Angular Speed
Angular speed equals 2π times frequency.
SHM Definition
In SHM, acceleration is proportional to displacement and directed toward equilibrium.
SHM Maximum Speed
Speed is greatest at equilibrium and zero at the turning points.
Damping
Damping removes energy and reduces amplitude with time.
Checkpoint rule
Do the check-up only after you can summarize each concept in one sentence and identify one dangerous pitfall from memory.
Knowledge Check (after reading)
Short check-up to confirm understanding of this module.
Check-up Questions
An object moves at constant speed in a circle. Why is it accelerating?
What is the direction of centripetal acceleration?
Answer all questions to submit.
Next step personalized recommendations
Continue learning
Move forward only after this module is stable.
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