1.4 Elasticity, Moments and Stability
Hooke's law, spring constant, elastic limit, moments, couples, equilibrium, centre of gravity and stability.
How to study for CCEA GCSE Physics
Link every equation to a physical model and unit, interpret graphs and evidence, and prepare each prescribed practical from method through evaluation.
Core concepts
Concept 1
Within the limit of proportionality, spring extension is proportional to force and the F-e gradient is the spring constant.
Exam cue: Confirm the CCEA unit, tier and whether the task tests a model, calculation, explanation or practical judgement.
Concept 2
A moment equals force multiplied by perpendicular distance from the pivot; balanced objects satisfy the Principle of Moments.
Exam cue: Use extension rather than total length, measure perpendicular distances and state clockwise and anticlockwise moments separately.
Concept 3
A low centre of gravity and wide base improve stability because the weight line remains within the base more readily.
Exam cue: Show substitutions and units, connect evidence to the physical model and limit the conclusion to the stated conditions.
Risk pitfalls and guardrails
Using the distance along a sloping force instead of the perpendicular distance to the pivot.
Guardrail: Do not import an England board, Single Award or Double Award structure, and do not replace a causal physical explanation with an equation alone.
Importing an equation sheet, Higher-only boundary or paper convention from an England 9-1 board.
Guardrail: Use the current CCEA formatting to confirm Higher-only content and the correct paper duration; do not infer tier scope from another exam board.
Giving a calculator display or named law without the working, units, causal explanation or evidence the command word requires.
Guardrail: Do not import an England board, Single Award or Double Award structure, and do not replace a causal physical explanation with an equation alone.
Memory anchors
Extension
Stretched length minus original length.
Spring constant
Force per unit extension within the proportional region.
Limit of proportionality
The point beyond which force and extension cease to be directly proportional.
Moment
Force multiplied by perpendicular distance from the pivot.
Principle of Moments
For equilibrium, total clockwise moment equals total anticlockwise moment.
Centre of gravity
The point through which an object's weight may be treated as acting.
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
A spring extends 0.040 m under a force of 6.0 N. What is its spring constant?
A spring is 12.0 cm long before loading and 15.5 cm after loading. What is its extension?
Answer all questions to submit.
Next step personalized recommendations
Continue learning
Move forward only after this module is stable.
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