Lesson Plan

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Lesson Plan
Grade: Date: 17/01/2026
Subject: Physics
Lesson Topic: state and apply the principle of moments
Learning Objective/s:
  • State the two conditions required for a rigid body to be in static equilibrium.
  • Explain the principle of moments and derive the relationship F₁d₁ = F₂d₂.
  • Apply moment calculations to solve problems involving levers, uniformly loaded beams, and ladders.
  • Identify common errors when using moments and correct them.
Materials Needed:
  • Projector and screen
  • Whiteboard and markers
  • Lever and beam models or printable diagrams
  • Worksheet with practice questions
  • Scientific calculators
  • Ruler or measuring tape
 Introduction:
Imagine balancing a seesaw so that it stays level – that’s the principle of moments in action. Students already know how to add forces as vectors, which will help them understand why forces alone are not enough for rotational balance. Today they will be able to state the equilibrium conditions and calculate unknown forces or distances using moment equations.
Lesson Structure:
  1. Do‑now (5 min): short quiz on the vector sum of forces.
  2. Mini‑lecture (10 min): introduce the two equilibrium conditions and define moment M = F × d with examples.
  3. Guided demonstration (10 min): use a lever model to calculate an unknown force via F₁d₁ = F₂d₂.
  4. Collaborative activity (15 min): groups solve a uniform‑beam‑support problem from the worksheet; teacher circulates.
  5. Whole‑class discussion (10 min): share solutions, highlight common mistakes from the source notes.
  6. Worked example walkthrough (10 min): step‑by‑step solution of the 2 m rod‑pin problem.
  7. Exit ticket (5 min): write the two equilibrium conditions from memory.
Conclusion:
We reviewed the conditions for static equilibrium and practiced applying the principle of moments to a variety of situations. The exit ticket confirms that students can recall the key concepts, and the worksheet will be completed for homework to reinforce the skill set. Homework: finish the three practice questions on levers, beams, and ladders and be ready to discuss solutions in the next lesson.