IB DP Physics circular motion lesson pack: centripetal force and free-body diagrams, Topic A.2 Forces and momentum, SL and HL, first assessment 2025: what makes a body go round a circle. Editable worksheet, 69-slide lesson deck, teacher key, worked solutions and a questions-only assessment, supplied as self-contained HTML plus colour and black-and-white PDF.
What students learn
- Centripetal force is a job, not a new force: the resultant of the real forces, towards the centre and perpendicular to the velocity.
- Four cases, four real forces: an orbit, a conical pendulum, a car on a roundabout and a cyclist on a banked track.
- F = mv²/r = mω²r from Newton’s second law, resolving a tension that does not act along the radius.
- Why the direction changes but the speed does not, and why on a vertical circle it can.
- Vertical circles, at the top and the bottom only: tension, normal force and the least speed, v = √(gr).
IB skills (Tool 3: Mathematics, with Inquiry 3: Concluding and evaluating):
- Draw and interpret free-body diagrams (practised).
- Resolve vectors (practised).
- Select and manipulate equations (practised).
- Propagate uncertainties in processed data (practised).
- Draw and interpret uncertainty bars (practised).
- Identify and discuss random and systematic errors (practised).
What’s included:
- Student Worksheet - 22 pages
- Teacher Key - 41 pages
- Worked Solutions - 26 pages
- Assessment - 16 pages
- Lesson deck - 69 slides
Ten structured questions and five multiple-choice items: 77 marks across 41 parts, and thirteen figures, seven with answer layers stripped from the student copy, not hidden. Six questions, 38 marks, are worked in the room; the rest go home, including a ten-mark data question in the Paper 1B pattern: a whirled bung, one point to add with its error bar and a systematic error to explain.
Banked bends are drawn, never calculated, as the guide asks. As the topic’s last lesson it carries all eight of the guide’s A.2 linking questions, each where it connects, and a Nature of Science box. Worksheet and deck open in any modern browser with nothing to install, and the worksheet is fully editable. SI units, IB notation and IB command terms throughout. Suitable for grades 11-12 (ages 16-19) as a lesson, cover lesson, homework or revision.
Related resources:
- Circular Motion I: Angular Velocity and Centripetal Acceleration, the lesson before this one
- Topic A.2 Test: Forces and Momentum, the topic test
- Free-Body Diagrams and Force Pairs, where free-body diagrams are taught
- Measuring the Acceleration of Free Fall, where error bars are taught (free)
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£9.00