Equations

density (kg/m³)

mass (kg) / volume (m³)

change in thermal energy (J)

mass (kg) x specific heat capacity (J/kg°C) x change in temperature (°C)

thermal energy for change in state (J)

mass (kg) x specific latent heat (J/kg)

Boyle’s law

pressure (Pa) x volume (m³) = constant

pressure due to a column of liquid (Pa)

height of column (m) x density of liquid (kg/m³) x gravitational field strength (N/kg)

suvat

(final velocity (m/s))² - (initial velocity (m/s))² = 2 x acceleration (m/s²) x distance (m)

distance (m)

speed (m/s) x time (s)

acceleration (m/s²)

change in velocity (m/s) / time (s)

kinetic energy (J)

½ x mass (kg) x (velocity (m/s))²

force (N)

mass (kg) x acceleration (m/s²)

momentum (kgm/s)

mass (kg) x velocity (m/s)

work done (J)

force (N) x distance (m) → distance needs to be along the line of action of the force

power (W)

energy (J) / time (s)

work done (J) / time (s)

current (A) x voltage (V)

(current (A))² x resistance (Ohms)

energy transferred in stretching (J)

½ x spring constant (N/m) x (extension (m))²

force exerted by a spring (N)

spring constant (N/m) x extension (m)

weight (N)

mass (kg) x gravitational field strength (N/kg)

gravitational potential energy (J)

mass (kg) x gravitational field strength (N/kg) x height (m)

pressure (Pa)

force normal to the surface (N) / area of the surface (m²)

moment (Nm)

force (N) x distance normal to the direction of the force (m)

charge flow (C)

current (A) x time (s)

potential difference (V)

current (A) x resistance (Ohms)

electrical energy transferred (J)

charge (C) x potential difference (V)

energy transferred (J, kWh)

power (W, kW) x time (s, h)

force on a conductor (at right angles to a magnetic field) carrying a current (N)

magnetic field strength (T) x current (A) x length (m)

transformers

v(primary) / v(secondary = n(primary) / n(secondary)

wave speed (m/s)

frequency (Hz) x wavelength (m)

efficiency

useful output energy transfer / total input energy transfer

P8.2

v(primary) x I(primary) = v(secondary) x I(secondary)