LuduminaFM-11 · FM-U4 · Planned
Newton’s first and third laws
Learning objectives
Apply first-law motion rules; identify third-law pairs acting on different objects; H: explain inertia.
8463 §§4.5.6.2.1,4.5.6.2.3 / 8464 §§6.5.4.2.1,6.5.4.2.3
DfE single-science pp.35–37 / Combined pp.30–32. Evidence checked 30 September–1 October 2026. Skills: WS1.2,3.6.
Explanation
Newton’s first law concerns forces on one body and unchanged velocity when their resultant is zero. Third-law pairs act on different bodies, so they do not cancel each other in a free-body diagram for a single object.
Concepts, equations and units: Zero resultant → unchanged velocity; interaction forces equal/opposite on different bodies; N.
Prediction, demonstration and game exercise
Predict, observe, explain
Predict a low-friction cart continuing after a push; compare book–table interaction with forces on the book.
Planned learner game exercise
Sort force-pair cards and remove an erroneous arrow from a selected free-body diagram.
Independent practice
Explain three equilibrium/motion cases including a steady-moving cart.
Original practice example · Shared
A book rests on a table. Is the book’s weight and the table’s force on the book a third-law pair?
Show working and model answer
Working / reasoning
Both act on the book. The partner of table-on-book is book-on-table; the partner of Earth-on-book is book-on-Earth.
Answer
No. Each third-law pair acts on two different bodies.
Exit check and success criteria
Two accurate cases plus a third-law pair on distinct bodies; H vocabulary used meaningfully.
During practice, compare the prediction with evidence and give an error-specific prompt. The exit item uses a fresh context or fresh values, answered independently.
Misconceptions, practical links and mastery
Check these misconceptions
A continuing force is required for steady velocity; weight and normal force on a book are a third-law pair.
Practical preparation
Optional cart and force-sensor demonstrations.
Virtual preparation and revision only. Required hands-on activities and school records remain separate.
Proposed mastery
0: not yet evidenced. 1: supported. 2: independent exit criteria met. 3: successful changed-context transfer. Advance at 2; revisit with fresh retrieval. These are not GCSE grades.