9478 / 2027

Chapter 2

Forces and Moments

Choose a body and identify the forces on it before calculating their resultant or turning effect.

Build a force model and use it to explain or calculate equilibrium.

Field and contact forces, upthrust, Hooke's law, moments, couples, centre of gravity and equilibrium. For 9478 (2027).

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Choose a topic

  1. Identify the body and its forces

    Distinguish field and contact forces and draw only the external forces on the chosen body.

  2. Springs and Hooke's law

    Calculate extension, use the force constant and interpret a force-extension investigation.

  3. Moments, couples and centre of gravity

    Find the perpendicular moment arm and distinguish a couple from a single force or a third-law pair.

  4. Combine force and moment balance

    Find support forces and tensions using moments, components and closed vector triangles.