| Lesson Plan |
| Grade: |
Date: 25/02/2026 |
| Subject: Physics |
| Lesson Topic: Apply the principle of moments to situations with one force each side of the pivot, including balancing of a beam |
Learning Objective/s:
- Describe the concepts of force, pivot, lever arm, and moment.
- Explain the principle of moments and the condition for rotational equilibrium.
- Apply the moment equation to calculate unknown forces or distances in a beam with one force on each side.
- Solve balanced‑beam problems using algebraic manipulation.
- Identify common errors when applying the principle of moments.
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Materials Needed:
- Whiteboard and markers
- Projector with slide showing beam diagram
- Ruler or metre rule for demonstration
- Set of masses (e.g., 20 N, 30 N) and a pivot stand
- Worksheet with practice questions
- Calculator (optional)
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Introduction:
Begin with a quick demonstration: hang two unequal masses on a simple beam to show it tilts. Ask students what determines the balance point, linking to prior knowledge of forces and distances. Explain that today they will learn how to predict and calculate the balance using the principle of moments. Success will be measured by correctly solving a beam‑balancing problem.
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Lesson Structure:
- Do‑now (5') – Students answer a short question on force and lever arm on a worksheet.
- Mini‑lecture (10') – Review key concepts, derive M = F·d, and introduce a sign convention for clockwise/anticlockwise moments.
- Guided demonstration (10') – Using the beam stand, show how changing distance changes balance; calculate the balance point together.
- Collaborative problem solving (15') – Small groups work through the worked example and one practice question while the teacher circulates.
- Whole‑class feedback (5') – Groups share solutions and discuss common mistakes.
- Exit ticket (5') – Each student writes the equilibrium condition for a new scenario.
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Conclusion:
Summarise that equilibrium is achieved when clockwise and anticlockwise moments are equal and that setting up the equation correctly leads to the unknown value. Emphasise the step‑by‑step process used today. For the exit ticket, students record the distance needed for a given force to balance the beam. Homework: complete the remaining practice questions in the worksheet.
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