Lesson Plan

• Describe the concept of a couple and how it differs from a single force.
• Explain why a couple produces pure rotation with zero resultant force.
• Calculate the torque of a couple using τ = F d.
• Apply the concept to real‑world examples such as a steering wheel or wrench.
• Analyse torque diagrams to determine the direction of rotation.

• Projector and screen
• Whiteboard and markers
• Printed worksheet with torque and couple problems
• Set of force‑vector cards
• Wrench (or similar lever) for demonstration
• Ruler and calculators

Begin with a quick demonstration of turning a steering wheel to highlight how opposite hands create rotation. Review students’ prior knowledge of torque and the vector cross‑product. State that by the end of the lesson they will be able to identify a couple, compute its torque, and distinguish it from a single force.

1. Do‑now (5') – short quiz on torque definition, units and direction.
2. Mini‑lecture (10') – introduce the definition of a couple, conditions (equal magnitude, opposite direction, parallel lines of action) and the formula τ = F d, using a diagram.
3. Guided demonstration (8') – use a wrench to show a real‑world couple and calculate its torque together.
4. Group activity (12') – students work on practice questions from the worksheet, modelling couples with force cards.
5. Concept check (5') – teacher asks probing questions; students respond via clickers or show of hands.
6. Summary & reflection (5') – recap key points; students write an exit‑ticket sentence stating the torque formula and an example.

Recap that a couple generates a constant torque independent of the reference point, producing pure rotation. Collect exit tickets where each student records the torque formula and one everyday example. For homework, assign two additional couple problems from the textbook to reinforce calculation skills.