Mechanics 1
Topic Brief: Resultant Forces and Bearings
Provenance: written 2026-09-29. Sources read for this pass: research/veridian/WME01-verified-facts.md (§1 spec text, §4 topic 2 in full, §5 the 17-series archive count, §6, §9 lines 295–316 — the lesson's own audit-trail entries); content/veridian/curriculum/wme01/resultant-forces-and-bearings.ts (header and citations, not its worked content); and, to confirm this document is genuinely additive, the existing WME01 technique-hub set in full — codex-deep-dive-resultant-forces-and-bearings.md, codex-formula-and-method-bank.md §1.3/§2.1–§2.2, forge-exam-technique-guide.md §1, signal-frequency-and-boundaries.md §1 — plus content/veridian/question-bank/wme01.ts (one item on this spec territory, Jan 2025 Q1(b), cross-checked for overlap). No new primary-source PDF was fetched this pass; every claim below traces to one of the documents just named, each of which already names the real mark scheme, examiner report or question paper it came from.
SIGNAL · Topic Master Brief — Resultant Forces and Bearings
Pearson Edexcel IAL Mechanics 1 (WME01/01), spec 2.1–2.2
What this adds that CODEX and FORGE don't: the CODEX deep-dive for this topic already lists every real exam angle sub-case by sub-case, with a micro-check for each; FORGE's tables tag two full series question-by-question. This brief does neither — it collapses both into the one practical question a candidate actually has 90 seconds to answer in an exam: if this topic shows up, what shape will it be, and what should I already be braced for? Every count below is re-derived from the same primary evidence CODEX and FORGE already cite, not copied from their tables uninspected.
1. Every real series this topic has been traced to
| Series | Question | Marks | What was actually tested | Mined |
|---|---|---|---|---|
| Jan 2022 | Q1 | 6 (two 3-mark parts) | Lami's theorem cited as a credited alternative to resolving — inside a three-force equilibrium question, not a bearings question | Full |
| Jan 2023 | Q6 | not recovered | Same alternative-method citation, independent series | One sentence only |
| Jun 2024 | Q2 | 4 (magnitude only) | Resultant of two forces: resolve-and-Pythagoras vs. cosine rule on a triangle of forces | Full |
| Jun 2024 | Q7(a) | 2 | Bearing → i/j component conversion | Full |
| Jun 2024 | Q7, continuation | not separately recovered | Relative position of two moving particles, minimum separation by differentiation | Full, single-series |
| Jan 2025 | Q1(a)–(b) | 8 (shared w/ 4.1) | Resultant of three named forces, then a fourth force added under a resultant-direction constraint | Full |
| Jan 2025 | Q5(b) | 4 (of Q5's 7) | Position vector at time t, then distance to a stated fixed point | Full |
| Jun 2025 | Q2 | 7 | "Relative position, bearing" | Spec-tag only |
| Jun 2025 | Q7 | 13 (shared w/ 3.1) | "Relative motion of two particles, a meeting condition" | Spec-tag only |
Seen in 5 of 17 series checked — 17 is the facts bank's own count of series with at least one genuine primary document reviewed (§5), not a claim that all 17 were individually screened for this exact spec point. Of those 5, 3 carry the topic's own core question type — a bearing, a resultant, or a position vector genuinely being the subject of the question (Jun 2024, Jan 2025, Jun 2025). The other 2 (Jan 2022, Jan 2023) only cite Lami's theorem as a credited alternative method inside an equilibrium question — real evidence that this lesson's own Lami's-theorem content is exam-relevant, but not evidence of a standalone bearings/resultant question in either series. The remaining 12 series were never tagged topic-by-topic for this spec point; their absence here means no document reviewed happened to record it, not that the topic was absent.
2. Mark-tariff pattern
No single fixed tariff — the range runs from a 2-mark bearing-conversion sub-part (Jun 2024 Q7(a)) up to a 13-mark blended question (Jun 2025 Q7). Two real patterns sit inside that range:
- Bare, single-mechanism appearances score small: 2 marks for a bearing conversion alone, 4 marks for a two-force resultant's magnitude alone (Jun 2024's two instances).
- The two most recently mapped series score this topic considerably higher — 7 to 13 marks — because in both, the vectors content is blended into a second spec area rather than standing alone: Jan 2025 Q1 folds a resultant into a Newton's-second-law direction constraint (2.1/4.1); Jun 2025 Q7 folds relative position into a kinematics meeting condition (2.1/2.2/3.1). Question position varies too — Q1, Q2, Q5 and Q7 all appear across the series checked, so "early" or "late" is not a safe assumption either way.
3. Recurring context or angle type
The one real shift visible across the dated evidence: Jun 2024's two appearances are each a bare, self-contained mechanism (one bearing, one two-force resultant); both series checked since then blend the same vector skills into a second topic — a follow-up force under a direction constraint (Jan 2025 Q1), or two moving particles' relative position feeding a meeting or minimum-separation condition (Jan 2025's Q7-family territory in Jun 2024, and again in Jun 2025 Q2/Q7). That is two data points confirming the blend, not a rule — but it means "bearings and resultants always arrive as a clean, isolated calculation" is already contradicted by the two most recent series this course has fully checked.
4. If this topic appears — what to expect
- Going by the two most recently fully-mapped series (Jan 2025, Jun 2025), expect this topic blended with Newton's second law or with kinematics — a resultant or a position vector as the opening step of a longer question — more than as a bare, stand-alone bearing/resultant calculation.
- Whichever form appears, the two specifically-verified traps for this exact spec point are (a) the bearing sin/cos pairing swap, confirmed to produce the exact wrong answer "12i + 16j" in a real series, and (b) substituting the raw angle between two forces — not its supplement — into the cosine rule. Both are confirmed in exactly one series each (Jun 2024) and both are already covered in full in the lesson's own trap-taxonomy and in CODEX §2.2/§2.5 — not re-derived here.
- If Lami's theorem appears, the evidence says to expect it inside an equilibrium (spec 5.1–5.3) question as a named, credited alternative method, not as a bearings question's own subject.
Sources and cross-references
research/veridian/WME01-verified-facts.md§1, §4 (topic 2), §5, §6, §9 (lines 295–316).codex-deep-dive-resultant-forces-and-bearings.md— the full sub-case-by-sub-case treatment and its own §3 table, which this brief re-sorts into a practical frequency/expectation view rather than repeats.forge-exam-technique-guide.md§1 — source of the Jun 2025 rows above.signal-frequency-and-boundaries.md§1 — the "2 of 2 series" full-mark-map basis this brief's Jan/Jun 2025 rows also rest on.content/veridian/question-bank/wme01.ts— Jan 2025 Q1(b)'s real mark-scheme working, cited for the direction-constraint fact only.
Genuinely unresolved
- Jun 2025 Q2 and Q7 are confirmed by FORGE's spec-tag only — no mark scheme or examiner report has been mined for either, so no trap or method preference can yet be claimed for them.
- Jan 2023 Q6's own marks were never recovered.
- Whether this topic appears, in any form, in any of the other 12 archive series is genuinely unknown, not ruled out.