Unit 2 · 2.2 — Forces and Free-Body Diagrams

Everything to learn here

• Concept: Force is a vector quantity resulting from a macroscopic interaction between two objects; it causes acceleration, not velocity.
• Concept: Free-body diagrams (FBDs) represent all external forces acting on an object as vectors originating from a single central dot.
• Concept: Force vectors on an FBD must be drawn proportionally to represent relative magnitudes and the resulting net acceleration accurately.
• Concept: Forces are vectors; the net force is the vector sum of all individual forces acting on an object.
• Vocabulary: Force — A push or pull resulting from an interaction between two objects.
• Vocabulary: Free-Body Diagram (FBD) — A visual model showing external force magnitudes, directions, and points of application.
• Skill: Creating Representations — Drawing FBDs where each force is a distinct, labeled arrow starting exactly on the point particle and pointing outward in the correct direction.
• Skill: Common Error Avoidance — Never include vector components, velocity vectors, or a "net force" arrow on an official, rubric-scored free-body diagram.
• Concept: Forces are vector quantities from external interactions; a system cannot exert a net force on itself.

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