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#deck:Brainlag::GCSE Physics equations
#tags:brainlag gcse-physics
Weight	W = mg, weight (N) = mass (kg) × gravitational field strength (N/kg)
Work done	W = Fs, work done (J) = force (N) × distance moved along the line of the force (m)
Force on a spring	F = ke, force (N) = spring constant (N/m) × extension (m)
Moment of a force (physics only)	M = Fd, moment (N m) = force (N) × perpendicular distance to the pivot (m)
Pressure (physics only)	p = F / A, pressure (Pa) = force normal to the surface (N) ÷ area of the surface (m²)
Distance travelled	s = vt, distance travelled (m) = speed (m/s) × time (s)
Acceleration	a = Δv / t, acceleration (m/s²) = change in velocity (m/s) ÷ time (s)
Resultant force	F = ma, resultant force (N) = mass (kg) × acceleration (m/s²)
Momentum (HT)	p = mv, momentum (kg m/s) = mass (kg) × velocity (m/s)
Kinetic energy	Eₖ = ½mv², kinetic energy (J) = ½ × mass (kg) × speed² (speed in m/s)
Gravitational potential energy	Eₚ = mgh, gravitational potential energy (J) = mass (kg) × gravitational field strength (N/kg) × height (m)
Power, from energy and time	P = E / t, power (W) = energy transferred (J) ÷ time (s)
Power, from work done and time	P = W / t, power (W) = work done (J) ÷ time (s)
Efficiency, from energy	Efficiency = useful output energy (J) ÷ total input energy (J). Efficiency has no unit; multiply by 100 for a percentage.
Efficiency, from power	Efficiency = useful power output (W) ÷ total power input (W). Efficiency has no unit; multiply by 100 for a percentage.
Wave speed	v = fλ, wave speed (m/s) = frequency (Hz) × wavelength (m)
Charge flow	Q = It, charge flow (C) = current (A) × time (s)
Potential difference	V = IR, potential difference (V) = current (A) × resistance (Ω)
Power, from potential difference and current	P = VI, power (W) = potential difference (V) × current (A)
Power, from current and resistance	P = I²R, power (W) = current² (current in A) × resistance (Ω)
Energy transferred, from power and time	E = Pt, energy transferred (J) = power (W) × time (s)
Energy transferred, from charge and potential difference	E = QV, energy transferred (J) = charge flow (C) × potential difference (V)
Density	ρ = m / V, density (kg/m³) = mass (kg) ÷ volume (m³)
Motion with a steady acceleration	v² − u² = 2as, final velocity² (final velocity in m/s) − initial velocity² (initial velocity in m/s) = 2 × acceleration (m/s²) × distance (m)
Force and momentum (physics only, HT)	F = mΔv / Δt, force (N) = mass (kg) × change in velocity (m/s) ÷ time taken (s)
Elastic potential energy	Eₑ = ½ke², elastic potential energy (J) = ½ × spring constant (N/m) × extension² (extension in m). This holds while the limit of proportionality is not passed.
Specific heat capacity	ΔE = mcΔθ, change in thermal energy (J) = mass (kg) × specific heat capacity (J/kg °C) × temperature change (°C)
Specific latent heat	E = mL, thermal energy for a change of state (J) = mass (kg) × specific latent heat (J/kg)
Period	T = 1 / f, period (s) = 1 ÷ frequency (Hz)
Magnification of a lens (physics only)	Magnification = image height ÷ object height. No unit: measure both heights in the same unit, such as mm.
Force on a conductor (HT)	F = BIl, force (N) = magnetic flux density (T) × current (A) × length of conductor in the field (m). The conductor is at right angles to the field.
Transformers (physics only, HT)	VₚIₚ = VₛIₛ, primary potential difference (V) × primary current (A) = secondary potential difference (V) × secondary current (A)
Turns ratio (physics only, HT)	Vₚ / Vₛ = nₚ / nₛ, primary potential difference (V) ÷ secondary potential difference (V) = primary turns ÷ secondary turns
Pressure in a liquid (physics only, HT)	p = hρg, pressure (Pa) = height of the column (m) × density (kg/m³) × gravitational field strength (N/kg)
Gas at constant temperature (physics only)	pV = constant, pressure (Pa) × volume (m³) = constant. For a fixed mass of gas.