Lesson Plan

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Lesson Plan
Grade: 12 Date: 17/01/2026
Subject: Physics
Lesson Topic: define and apply the torque of a couple
Learning Objective/s:
  • Define torque and the torque of a couple as vector quantities.
  • Explain why the torque of a couple is independent of the reference point.
  • Calculate the magnitude of a couple’s torque using τ = F d.
  • Apply the right‑hand rule to determine the sense of rotation of a couple.
  • Solve multi‑step problems involving couples and equilibrium conditions.
Materials Needed:
  • Projector and screen for slides/diagrams
  • Whiteboard and markers
  • Printed worksheet with example problems
  • Force‑vector cards for a classroom demonstration
  • Ruler or measuring tape for distance d
  • Calculator for each student
 Introduction:
Begin with a quick demonstration: twist a door handle while a second opposite force is applied, showing pure rotation. Recall previous learning on torque of a single force and the right‑hand rule. Today’s success criteria: students will be able to define a couple, compute its torque, and justify its direction.
Lesson Structure:
  1. Do‑now (5'): Students answer a short question on torque of a single force (worksheet). – check understanding.
  2. Mini‑lecture (10'): Define a couple, derive τ = F d, emphasize independence of reference point – projector slides.
  3. Guided practice (12'): Work through the example problem step‑by‑step; calculate torques and direction.
  4. Hands‑on activity (15'): In groups, use force cards and rulers to create couples, measure d, compute τ, record results.
  5. Concept check (8'): Quick Kahoot quiz with conceptual questions on couples vs single forces.
  6. Exit ticket (5'): Write one real‑world example of a couple and the associated torque calculation.
Conclusion:
Summarise that a couple produces pure rotation with torque τ = F d, independent of where it is measured. Students complete an exit ticket stating the net torque for a given scenario. For homework, assign a set of problems requiring identification of couples and calculation of their torques.