No formula list is supplied in the written papers, so you must recall every equation and key fact yourself. This sheet groups them by topic, marking the ones aimed at Extended students. Use it for regular recall practice, including the symbols, units and rearrangements, and check against your own syllabus level.
| Formula | Meaning, symbols and units | When you use it |
|---|
| speed = distance ÷ time | Speed (m/s), distance (m), time (s) | Constant or average speed |
| average speed = total distance ÷ total time | Whole journey, including any stops | Journeys with changing speed |
| acceleration = change in velocity ÷ time | a = (v − u) ÷ t, in m/s² | Speeding up and slowing down |
| gradient of a speed–time graph | Equals acceleration (m/s²) | Reading graphs |
| area under a speed–time graph | Equals distance travelled (m) | Finding distance from a graph |
| F = ma | Resultant force (N), mass (kg), acceleration (m/s²) | Newton's second law |
| W = mg | Weight (N), mass (kg), g = field strength (N/kg) | Mass to weight conversion |
| density = mass ÷ volume | ρ = m ÷ V; kg/m³ or g/cm³ | Floating, sinking, identifying materials |
| extension = new length − natural length | Extension in m or cm | Spring and stretching experiments |
| F = kx | Force (N), spring constant k (N/m), extension x (m) | Springs below the limit of proportionality |
| moment = force × perpendicular distance | N m, with distance measured to the pivot | Levers and turning effects |
| sum of clockwise moments = sum of anticlockwise moments | Balance condition about any pivot | Balanced beams |
| p = mv (Extended) | Momentum (kg m/s), mass (kg), velocity (m/s) | Collisions |
| impulse = Ft = Δ(mv) (Extended) | Impulse (N s), force (N), time (s) | Impact forces and safety |
| Formula | Meaning, symbols and units | When you use it |
|---|
| work done = force × distance moved | W = Fd in J | Mechanical work |
| KE = ½mv² | Kinetic energy (J), mass (kg), speed (m/s) | Moving objects |
| GPE = mgh | Gravitational potential energy change (J), height change h (m) | Lifting and falling |
| power = work done ÷ time | P in W, W in J, t in s | Rate of working |
| power = energy transferred ÷ time | Same relation with energy in J | Appliances and machines |
| efficiency = useful output ÷ total input × 100% | Energy or power values in the same unit | Energy devices |
| p = F ÷ A | Pressure (Pa or N/m²), force (N), area (m²) | Pressure from solids |
| Δp = ρgΔh (Extended) | Pressure change in a liquid (Pa), density (kg/m³), depth change (m) | Pressure in liquids |
| Formula | Meaning, symbols and units | When you use it |
|---|
| ΔE = mcΔθ | Energy (J), mass (kg), specific heat capacity c (J/kg °C), temperature change (°C) | Heating and cooling |
| c = ΔE ÷ (mΔθ) | Specific heat capacity rearranged | Heating experiments |
| E = ml | Energy (J), mass (kg), specific latent heat l (J/kg) | Changing state (Extended) |
| T(K) = θ(°C) + 273 | Kelvin and Celsius conversion | Gas laws |
| pV = constant | Fixed mass and temperature | Gas compressed or expanded (Extended) |
| p₁V₁ = p₂V₂ | Pressure and volume before and after a change | Gas problems (Extended) |
| Formula | Meaning, symbols and units | When you use it |
|---|
| v = fλ | Wave speed (m/s), frequency (Hz), wavelength (m) | All wave calculations |
| f = 1 ÷ T | Frequency (Hz) and period (s) | Oscillations and waves |
| n = sin i ÷ sin r | Refractive index; angles measured from the normal | Refraction |
| n = speed in vacuum ÷ speed in medium (Extended) | Refractive index without units | Light in glass or water |
| sin c = 1 ÷ n (Extended) | Critical angle c | Total internal reflection |
| magnification = image height ÷ object height | No units | Lenses and magnifying glasses |
| speed of sound = distance ÷ time | Use twice the distance for echoes | Echo experiments |
| angle of incidence = angle of reflection | Both measured from the normal | Mirrors and plane reflection |
| speed of light ≈ 3.0 × 10⁸ m/s | Speed of electromagnetic waves in a vacuum | Radio, light and space distances |
| Formula | Meaning, symbols and units | When you use it |
|---|
| Q = It | Charge (C), current (A), time (s) | Charge flow |
| V = IR | Potential difference (V), current (A), resistance (Ω) | Resistor circuits |
| P = IV | Power (W), current (A), potential difference (V) | Electrical power |
| E = IVt | Energy (J), time (s) | Energy used by a device |
| R = R₁ + R₂ | Series resistors (Ω) | Series circuits |
| 1/R = 1/R₁ + 1/R₂ (Extended) | Parallel resistors (Ω) | Parallel circuits |
| R ∝ l ÷ A (Extended) | For wires of the same material, resistance is proportional to length l and inversely proportional to cross-sectional area A | Comparing wires of different size |
| potential divider: V₁ = V × R₁ ÷ (R₁ + R₂) (Extended) | Share of the supply voltage across a resistor | Sensor circuits |
| Vp ÷ Vs = Np ÷ Ns (Extended) | Transformer voltage and turns ratio | Transformers |
| VpIp = VsIs (Extended) | Power in equals power out for an ideal transformer | Transformer currents |
| Formula | Meaning, symbols and units | When you use it |
|---|
| A = Z + N | Nucleon number, proton number, neutron number | Nuclear notation |
| remaining fraction = (½)ⁿ | n = number of half-lives | Half-life questions |
| alpha decay: A − 4, Z − 2 | Changes after emitting an alpha particle | Decay equations |
| beta decay: A same, Z + 1 | Changes after emitting a beta particle | Decay equations |
| gamma emission | No change in A or Z; excess energy is emitted | Decay equations |
| orbital speed = 2πr ÷ T | Speed (m/s), orbital radius (m), orbital period (s) | Planets and satellites |
| v = H₀d (Extended) | Recession speed related to distance, using the given constant | Expanding Universe |