Mechanics 1

Battle Card

Provenance: written 2026-09-29. This card adds nothing new to the primary-source record — every fact below already lives in research/veridian/WME01-verified-facts.md (17 series, Oct 2018–Jun 2025, including the Jan 2025/Jun 2025 deep-read), forge-exam-technique-guide.md, codex-formula-and-method-bank.md, and signal-frequency-and-boundaries.md, all checked against this card before writing it so nothing here contradicts them. What this card does that none of those four documents do: compress the whole paper — every spec point, not one topic — onto one dense, skim-in-under-five-minutes reference meant for the last few minutes before you go in, not for learning the material. No worked examples, no prose explanation, no self-mark checklist walkthrough — those stay in FORGE/CODEX/the lesson files, cited by name below rather than repeated. Where this card ranks or clusters traps across topics (the Top 5, §4), that ranking itself is new synthesis, not present as a single ordered list anywhere else in this hub; every item in it still traces to the named series already verified elsewhere.

#FORGE · WME01 Battle Card

#Pearson Edexcel IAL Mechanics 1 (WME01/01) — last look before you walk in

#0. The three facts that decide everything else

The formula booklet gives M1 nothing. Its entire M1 entry (p.13) is two sentences saying so. Every formula in §1 below is 100% recall — there is nothing M1-shaped to look up in the exam room. The one real exception: the cosine rule (a P1/P2 formula the booklet extends to M1, confirmed live in Jun 2024 Q2).
g = 9.8. Always. Not 9.81, not 10. It's printed on the front of the paper. Round final answers to 2 or 3 sf. Round only at the end — premature rounding mid-working is penalised every time it happens, not once per question.
75 marks, 90 minutes, every question compulsory. Question count is usually 8, occasionally 7 (Jan 2019, Oct 2023) — never assume 8 and panic if the paper in front of you isn't. No non-calculator section exists on this paper; a calculator with no symbolic algebra/calculus is required, not optional.

#1. Formula quick-fire, every spec point, in memorise order

2.1–2.2 Vectors

Resolve along/perpendicular to a stated direction: F cos θ / F sin θ.
Bearing → components (bearings are clockwise from North — sin/cos are swapped from the usual x-axis convention): East(i) = F sin θ, North(j) = F cos θ.
Magnitude: |v| = √(x² + y²).
Resultant of two forces, angle θ between them: R² = P² + Q² + 2PQ cos θ (parallelogram law) — or sum every i, every j, then Pythagoras.
Cosine rule (triangle of forces, GIVEN in the booklet): a² = b² + c² − 2bc cos A — use the triangle's own interior angle (180° − θ), not θ itself.
Lami's theorem (accepted alt., not spec-named): P/sin α = Q/sin β = R/sin γ.
Position under constant velocity: r(t) = r₀ + tv. (Not a 2D projectile equation — this spec's kinematics is straight-line only; the vector content is constant-velocity position, full stop.)

3.1 Kinematics

All five, all memorised: v = u+at · s = ut+½at² · s = vt−½at² · v² = u²+2as · s = ½(u+v)t.
v-t graph: gradient = a, area = s (the area formula is the fifth suvat equation).
Graph shape starts where the object's own motion actually starts (not automatically the origin); never draw a continuous line where the motion has a real corner or gap.

4.1 Dynamics / N2L

F = ma, F = the resultant, never one applied force alone.
Vector form: F₁+F₂+... = ma, matched component by component — one i-equation, one j-equation, two separate things to solve, not one.

4.2 Connected particles — not a formula, a method identity: each particle gets its own equation, its own direction of motion positive for that particle, linked by shared T and shared a. Two particles in series ≠ automatically a pulley — read the stem.

4.3 Momentum / impulse

momentum = mv · impulse = mv − mu.
Conservation (direct collision): m₁u₁ + m₂u₂ = m₁v₁ + m₂v₂. Every velocity here is signed.

4.4 / 5.3 Friction

Moving: F = μR. Equilibrium/limiting: F ≤ μR, = μR only exactly at the point of slipping.

5.1–5.2 Statics

W = mg (a force, not a mass — don't write "5g" when a question already gives you "5 N").
Equilibrium: ΣFₓ = 0 and ΣF_y = 0, both directions, every present force resolved with an actual sin/cos factor.

6.1 Moments

moment = force × perpendicular distance. A force acting at the pivot has zero moment there, whatever its own magnitude — this is the entire mechanism behind picking a smart pivot.
ΣM_clockwise = ΣM_anticlockwise, plus ΣF = 0 in the direction the forces act. Two unknown reactions → one moments equation (about either support) + one resolve, not two moments equations. Exception: if the rod's own weight or centre-of-mass position is also unknown, a second, genuinely independent moments equation is the correct method (Jan 2023 Q4).

1.1 Modelling vocabulary (one-line cues — full table: CODEX §1.2) particle = point mass, no rotation · lamina = flat 2D · rigid = doesn't bend · light = zero mass · uniform = weight at centre · non-uniform = weight at a stated point · inextensible = both ends same speed · smooth = no friction · rough = F=μR/F≤μR applies · light smooth pulley = same T both sides · bead/wire = constrained to a curve · peg = fixed point, smooth unless stated.

#2. Tariff reminders — how the marks actually land

M = correct method (or a genuine attempt at one). A = accuracy, only bankable once its M is banked — M0 A1 is impossible. B = stands alone, no M needed (often a graph or a stated comment). DM = a method mark that only fires once a specific earlier M is already banked.
An M mark has to look like real physics. Missing a mass from a resolution, or a length from a moments equation → the M mark itself is gone. Missing or adding an extra g in a resolution → the method still stands, only the accuracy mark is at risk.
Velocity-time/speed-time graphs carry their own direct B marks (shape, axis labels) — a solid line where the motion should show a corner or a gap loses the shape mark outright, confirmed in both 2025 series.
"Show that" built on an exact fraction (e.g. 3/5, 4/5) needs the exact fraction carried through the whole chain — a decimal substitution anywhere breaks the given-answer mark even if it rounds correctly.
Units are not usually an accuracy error if missing or wrong — write them anyway, don't burn time on them.
Misread the question but the working still shows a genuine method? Two marks off the A/B marks in that part, not the whole part — not a total wipeout.
More than one attempt left on the page? Cross out every version except the one you want marked. Leave it ambiguous and examiners mark every attempt, keeping only your best single one — worse odds than a clean single answer.
Mark-scheme shorthand, decoded for self-marking practice papers: bod benefit of doubt · ft follow-through (a later mark can use your own earlier, possibly wrong, value) · cao correct answer only · cso correct solution only start to finish · isw ignore subsequent (wrong) working after the mark is already earned · awrt answer which rounds to · SC a pre-written special case, full credit for one specific wrong-diagram/wrong-setup situation · oe or equivalent.

#3. Definition-cue fast recall

"About to tilt" ⇒ one named reaction = 0. (Confirmed trap: candidates zero the wrong reaction — check which support the rod is tilting about, not the one nearer the load.)
"Acts in the direction of..." ⇒ parallel to that vector, not equal to it — a vector equated straight to a direction (skipping the λ/ratio step) is a confirmed real error (Jan 2025 Q1(b)).
"Hence show that" ⇒ must actually use the stated earlier part(s), not a fresh independent derivation — and the final line must land on the exact printed target.
"Speed" vs "velocity" ⇒ decides whether the final answer must be unsigned or can stay signed. Re-read the exact word every single time; it can change between parts of the same question.
A force/reaction/tension found in one part is what "the acceleration"/"the tension" means later ⇒ not g, not a fresh unknown. Confirmed real mark-loss: defaulting back to g instead of a just-found system acceleration (Jan 2025 Q7(b)).
A support losing contact / a pivot changing ⇒ every force from the old picture that no longer applies must be dropped, not carried forward (Jan 2025 Q4).

#4. TOP 5 DANGER LIST — ranked by how many independently-checked series confirm it

1. Reporting a signed value where the question asked for an unsigned one. The single strongest cross-series trap in the whole archive. Seen in 4 of the 17 series checked: Jan 2020, Oct 2022, Jun 2024 (momentum "speed"), Jan 2025 (a kinematics deceleration, independently). Fix: fix your positive direction before the first equation, strip the sign only if the question's own word (speed/distance/magnitude) demands it.

2. Treating a motion that changes character partway through as one equation for the whole thing. Two related families, 4 named series total: kinematics two-stage motion (acceleration→deceleration, or free-fall→parachute) in Jan 2023 and Jun 2024; connected-particles pulley-then-free-motion (one particle lands, the other keeps moving under gravity alone) in Jan 2025 and Jun 2025 — the latter is this paper's own recent final, heaviest question shape. Fix: the moment the force system changes, the old equation is dead — write a fresh one for the new stage.

3. An equation that looks right but isn't dimensionally an equation of this system. Missing mass in a resolution or a length in a moments equation costs the method mark itself, not just accuracy — and Jan 2025 records a live equation with every term a genuine signed force but no ma/3ma anywhere in it, which (if solved) quietly describes a system in equilibrium instead of one accelerating. Fix: before solving, check every term is the right kind of quantity and that acceleration actually appears somewhere.

4. Moments: wrong reaction zeroed, a redundant second moments equation, or a stale force kept after the picture changes. Three series (Jan 2023, Jun 2024, Oct 2023) converge on the same pivot-choice rule and the same two-equations-where-one-would-do penalty; Jan 2025 Q4 adds a distinct variant — keeping a tension/particle from an earlier part after the rod has tilted and that support/force is no longer there. Fix: name which support the rod tilts about before writing anything, and re-draw the picture (don't just reuse the old one) once anything about it changes.

5. Vector/bearing conversion slips, clustered around Jun 2024 and Jan 2025. Four distinct, separately-confirmed errors in this cluster: bearing sin/cos pairing swapped (Jun 2024 Q7); the wrong angle (30°/60°/330° instead of the triangle's own interior angle) substituted into the cosine rule (Jun 2024 Q2); a direction vector mistaken for the resultant itself, skipping the λ-elimination step (Jan 2025 Q1(b)); a fully correct method left as a vector when the question asked for a magnitude (Jan 2025 Q1(a)). Fix: bearings swap sin/cos from the usual convention — say it out loud before resolving; finish every vector question by checking whether the answer the question wants is the vector, its magnitude, or a bearing.

#5. 60-second final scan

Positive direction fixed before the first equation — checked, not assumed.
Every resolved term actually carries sin/cos; every force present is actually in an equation somewhere.
g = 9.8 throughout; final answers 2–3 sf; no mid-working rounding.
"Show that" / "hence" — traced to the exact target, using the stated earlier part.
Final word check: speed or velocity, distance or displacement, vector or magnitude or bearing — does the last line match what was actually asked?
A negative answer for something that must be positive (speed, length, time) → find the broken sign assumption, don't just delete the minus.
A "does it move / stay in equilibrium" conclusion has an actual number comparison behind it, not prose alone.

(Full three-phase checklist, with the sourcing for each line: forge-exam-technique-guide.md §3.)

#6. Two numbers worth knowing, not more

Grade a (raw/75), most recent settled run: Jan 2023 52 → Jun 2023 67 → Jan 2024–Jun 2025 (4 straight series) at 64–65. One series can still move a lot (that 15-mark Jan→Jun 2023 jump is real) — don't treat 64–65 as guaranteed for your own sitting. Full 6-series, all-6-grade table: signal-frequency-and-boundaries.md §2.
Topic coverage: in the only two series checked question-by-question (Jan 2025, Jun 2025), every spec topic except modelling (1.1) anchored a real question, both times. Don't deprioritise anything on this paper on a "less likely" theory — the checked record doesn't support one. Full table: signal-frequency-and-boundaries.md §1.

#Sources

Every claim above traces to: the Pearson spec (Issue 3, April 2019) and formula booklet (Issue 2, January 2021), both read directly for research/veridian/WME01-verified-facts.md; the 17 mark-scheme/examiner-report series that facts bank names in its §5 (Oct 2018–Jun 2025); the two fully re-verified 2025 series in forge-exam-technique-guide.md §1/§2/§4; the Pearson grade-boundary PDFs (Jan 2023–Jun 2025) read for signal-frequency-and-boundaries.md §2; and codex-formula-and-method-bank.md Part 1 for the formula/booklet-status cross-check. No new primary-source document was fetched to write this card — its only job was compression and cross-topic ranking of material this course had already verified.