Forces, Newton's Laws and Stability
Apply force, mass, acceleration, momentum, centre of mass and stability principles to sporting situations.
How to study A-level Physical Education theory
Learn the mechanism, apply it to a precise sporting context, use quantitative or source evidence where relevant and reach a supported judgement.
Core concepts
Concept 1
Newton's laws explain inertia, acceleration under resultant force and paired action-reaction forces.
Exam cue: Draw or describe the forces acting on the selected performer or object before calculating.
Concept 2
Mass, weight, velocity, acceleration, momentum and impulse have distinct definitions, units and scalar or vector status.
Exam cue: Use the correct unit and direction for vector quantities.
Concept 3
Stability depends on centre of mass, base of support, line of gravity, body mass and external forces.
Exam cue: Explain the performance consequence of changing impulse, momentum or stability.
Targeted study blocks
Knowledge for written assessment
Secure the shared theoretical core
Learn force concepts, Newton's laws, mass and weight, momentum and impulse, centre of mass and the factors influencing equilibrium and stability.
Apply and evaluate
Turn knowledge into a supported sporting judgement
Represent the mechanics of a sporting example, complete any calculation and interpret whether the mechanical change helps the stated performance goal.
Risk pitfalls and guardrails
Treating action and reaction as cancelling forces on the same body.
Guardrail: Do not replace theoretical explanation with an activity-specific technique description or practical-performance instruction.
Confusing mass measured in kilograms with weight measured in newtons.
Guardrail: Do not replace theoretical explanation with an activity-specific technique description or practical-performance instruction.
Assuming a lower centre of mass always improves the goal of the movement.
Guardrail: Do not replace theoretical explanation with an activity-specific technique description or practical-performance instruction.
Memory anchors
Newton's first law
Motion remains unchanged unless a resultant external force acts.
Newton's second law
Resultant force equals mass multiplied by acceleration.
Newton's third law
Interacting bodies exert equal and opposite forces on one another.
Momentum
Linear momentum equals mass multiplied by velocity.
Stability
A wide base and low centre of mass generally increase stability when the line of gravity remains inside the base.
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
When analysing a ball's motion, which listed quantity is a vector?
A 70 kg sprinter accelerates at 3.0 m s⁻². What resultant horizontal force acts on the sprinter?
Answer all questions to submit.
Next step personalized recommendations
Continue learning
Move forward only after this module is stable.
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