Lesson Plan

• Describe the relationship between linear speed, radius, and angular speed in uniform circular motion.
• Explain why a radial (centripetal) acceleration exists even when speed is constant.
• Apply the formula $a_c = v^{2}/r = \omega^{2}r$ to calculate centripetal acceleration and force in typical problems.
• Identify and correct common misconceptions about centripetal force and centrifugal force.
• Conduct a simple experiment to verify centripetal acceleration using a turntable and spring balance.

• Projector and screen
• Whiteboard and markers
• Printed worksheet with worked example
• Low‑friction turntable, string, small masses
• Stopwatch and ruler
• Spring balance (force sensor)
• Scientific calculators

Begin with a short video of a ball on a string being whirled rapidly to capture interest. Review students’ prior knowledge of speed, force, and vector direction. State that by the end of the lesson they will be able to calculate and explain the centripetal acceleration that keeps an object moving in a circle at constant angular speed.

1. Do‑now (5 min): Quick quiz on vector components and Newton’s 2nd law.
2. Mini‑lecture (10 min): Derive $a_c = v^{2}/r = \omega^{2}r$ and relate $v = \omega r$.
3. Concept discussion (8 min): Address the three common misconceptions using Socratic questioning.
4. Guided worked example (10 min): Solve the whirling‑ball problem step‑by‑step.
5. Laboratory activity (15 min): Students measure period $T$ and radius $r$ on the turntable, compute $\omega$, $a_c$, and compare predicted force with a spring‑balance reading.
6. Check for understanding (5 min): Exit‑ticket – one sentence explaining why constant‑speed circular motion involves acceleration.

Summarise the key formulae and emphasise that centripetal acceleration always points toward the centre of the circle. Collect exit‑tickets and remind students to complete the worksheet with two additional circular‑motion problems for homework.