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How to Use This Page
Legend:
- Given – on the official Edexcel 4PH1 equation sheet (you’ll get this in the exam).
- Given (Paper 2) – on the sheet, but mainly needed for Paper 2 questions.
- Memorise – not on the sheet; you should remember or be able to derive it.
Even for “Given” formulas, practise using them until you can rearrange them in your sleep.
Topic 1
Forces & Motion
Speed, acceleration, forces, weight, momentum, moments.
Core Kinematics
average speed = distance moved ÷ time taken v = d / t
Given
acceleration = change in velocity ÷ time taken a = (v − u) / t
Given
(final speed)² = (initial speed)² + (2 × a × distance moved) v² = u² + 2 a s
Given
Forces, Weight & Resultants
force = mass × acceleration F = m a
Given
weight = mass × gravitational field strength W = m g
Given
Momentum & Moments (mainly Paper 2)
momentum = mass × velocity p = m v
Given (Paper 2)
force = change in momentum ÷ time taken F = (m v − m u) / t
Given (Paper 2)
moment = force × perpendicular distance from pivot
Given (Paper 2)
Useful Extras (Not on Sheet)
stopping distance = thinking distance + braking distance
Memorise
Hooke’s law (linear region): F = k × extension
Memorise
In questions with speed–time or distance–time graphs: gradient = speed/velocity, area under speed–time graph = distance.
Topic 2
Electricity
Charge, current, potential difference, resistance, power, energy.
Charge, Current & Voltage
charge = current × time Q = I t
Given
voltage = current × resistance V = I R
Given
energy transferred = charge × voltage E = Q V
Given
Power & Electrical Energy
power = current × voltage P = I V
Given
energy transferred = current × voltage × time E = I V t
Given
Useful Extras (Not on Sheet)
power in a resistor: P = I² R
Memorise
power in a resistor: P = V² / R
Memorise
series resistance: Rtotal = R₁ + R₂ + …
Memorise
parallel resistance: 1 / Rtotal = 1/R₁ + 1/R₂ + …
Memorise
Topic 3
Waves
Wave speed, frequency, refraction, critical angle.
Wave Speed & Frequency
wave speed = frequency × wavelength v = f λ
Given
frequency = 1 ÷ time period f = 1 / T
Given
Refraction & Critical Angle
refractive index = sin i ÷ sin r n = sin i / sin r
Given
sin critical angle = 1 ÷ refractive index sin c = 1 / n
Given
Useful Extras
echo distance: distance to wall = (speed of sound × time) ÷ 2
Memorise
Topic 4
Energy Resources & Energy Transfer
Work, GPE, KE, power, efficiency.
Work & Mechanical Energy
work done = force × distance moved W = F d
Given
gravitational potential energy = m g h
Given
kinetic energy = ½ × mass × speed² Ek = ½ m v²
Given
Power & Efficiency
power = work done ÷ time taken P = W / t
Given
efficiency = useful energy output ÷ total energy input
Given
efficiency (%) = (useful ÷ total) × 100%
Given
Topic 5
Solids, Liquids & Gases
Density, pressure, liquids, gas laws, specific heat capacity.
Density & Pressure
density = mass ÷ volume ρ = m / V
Given
pressure = force ÷ area p = F / A
Given
pressure difference = h × ρ × g p = h ρ g
Given
Gas Laws
pressure × volume = constant p₁ V₁ = p₂ V₂
Given
pressure ÷ temperature = constant (T in K) p₁ / T₁ = p₂ / T₂
Given
Thermal Energy (Paper 2)
change in thermal energy = mass × specific heat capacity × temperature change ΔQ = m c ΔT
Given (Paper 2)
Topic 6
Magnetism & Electromagnetism
Electromagnets, motor effect, transformers.
Transformers (Paper 2)
Vₚ ÷ Vₛ = Nₚ ÷ Nₛ
Given (Paper 2)
input power = output power (ideal) Vₚ Iₚ = Vₛ Iₛ
Given (Paper 2)
Motor Effect (Not on Sheet)
force on current-carrying wire: F = B I L
Memorise
Remember Fleming’s left-hand rule for directions (Force, Field, current).
Topic 7
Radioactivity & Particles
Nuclear notation, decay, half-life.
Nuclear Notation & Decay
alpha decay: AZX → A−4Z−2Y + 42He
Memorise (pattern)
beta-minus decay: AZX → AZ+1Y + 0−1e
Memorise (pattern)
Half-life (Useful Relationship)
N = N₀ × (½)t / T½
Memorise / derive
Edexcel usually tests half-life with graphs and step-by-step halving, but this equation helps you think about repeated halving.
Topic 8
Astrophysics
Orbits, circular motion, red-shift.
Orbital Motion
orbital speed = (2 π × orbital radius) ÷ time period v = 2πr / T
Given
Red-shift (Paper 2)
red-shift: Δλ ÷ λ = v ÷ c
Given (Paper 2)
Δλ is the change in wavelength, λ is the original wavelength, v is the speed of the galaxy, c is the speed of light.
Exam Tip
For each topic, ask yourself:
- Can I rearrange every formula for any letter?
- Do I know what each symbol and unit means?
- Do I know which ones are already printed for me, and which ones I must know?
If you can answer “yes” to those three for all the boxes above, you’re in a very strong place for the calculation questions.