| Lesson Plan |
| Grade: |
Date: 25/02/2026 |
| Subject: Physics |
| Lesson Topic: Describe, qualitatively, motion in a circular path due to a force perpendicular to the motion as: (a) speed increases if force increases, with mass and radius constant (b) radius decreases if force increases, with mass and speed constant (c) an incre |
Learning Objective/s:
- Describe how increasing centripetal force changes speed when mass and radius are constant.
- Explain how increasing centripetal force changes radius when mass and speed are constant.
- Analyse the quantitative relationship F = mv²⁄r and its qualitative implications.
- Predict the effect on motion when mass, speed, or radius is varied.
- Apply the formula to solve simple qualitative circular‑motion problems.
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Materials Needed:
- Projector and screen
- Whiteboard and markers
- Printed worksheet with diagram and practice questions
- Set of small toy cars with string (to demonstrate circular motion)
- Stopwatch
- Scientific calculators
- Student notebooks
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Introduction:
Begin with a quick video of a roller‑coaster loop to spark interest. Ask students what keeps the cars on the track and link this to prior knowledge of forces and motion. State that by the end of the lesson they will be able to explain and predict how changes in force, mass, speed, or radius affect circular motion.
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Lesson Structure:
- Do‑now (5'): Quick quiz on Newton’s laws and basic force concepts.
- Mini‑lecture (10'): Introduce centripetal force, derive F = mv²⁄r, and highlight that the force is always perpendicular to motion.
- Demonstration (10'): Use toy cars on a string to show (a) increasing pull (force) speeds the car, (b) increasing pull while keeping speed constant tightens the circle, (c) adding mass requires more pull.
- Guided Practice (15'): Students work in pairs on the worksheet, filling the summary table for each scenario and justifying their answers.
- Check for Understanding (5'): Whole‑class “thumbs‑up/down” on each qualitative relationship.
- Summary & Concept Mapping (5'): Consolidate the three key relationships on the board.
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Conclusion:
Recap the three qualitative effects of changing force, mass, speed, or radius on circular motion. Have students write one exit‑ticket sentence predicting the outcome of a new scenario. Assign homework: complete a set of problems applying F = mv²⁄r to different circular‑motion situations.
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