IP Physics Notes (Upper Secondary, Year 3-4): 3) Forces
Distinguish mass from weight, handle friction and upthrust, draw clean free-body diagrams, and apply Newton's laws with vector resolution.
Q: What does IP Physics Notes (Upper Secondary, Year 3-4): 3) Forces cover?
A: Distinguish mass from weight, handle friction and upthrust, draw clean free-body diagrams, and apply Newton's laws with vector resolution.
Quick recap -- Treat force as a vector, link weight to gravitational field strength, capture all pushes/pulls in a free-body diagram, and let Newton's laws plus vector resolution tell you whether motion changes.
The core idea is simple: Forces change motion only when the resultant force is not zero.
Use it as a working check: Draw the free-body diagram first. Separate mass from weight, include friction, tension, normal force, and upthrust, then resolve vectors before applying Newton's laws.
Then go one layer deeper: Use the force families and Newton's law sections to practise moving from a word problem to a labelled diagram, resultant force, and acceleration statement.
Keep your practice loop tight via our IP Physics tuition hub - it links each topic here to quizzes, diagnostics, and WA-style problem sets.
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These notes align with SEAB GCE O-Level Physics (6091) content used in IP programmes (exams from 2026).
Status: SEAB O-Level Physics 6091 syllabus (exams from 2026) checked 2025-11-30 - scope unchanged; remains the reference for these notes.
Force Fundamentals
- A force is a push or pull arising from interaction between bodies. It can change an object's speed, direction, or shape.
- Forces are vectors: they need both magnitude and direction. The SI unit is the newton .
- Typical families you must recognise: weight (gravity), normal contact, friction, tension, upthrust, and applied pulls/pushes.
Mass, Weight & Gravitational Fields
- Mass measures the amount of matter and inertia an object has. It stays constant wherever you go.
- Weight is the gravitational force on that mass. Close to Earth,
