Equations

• Kinetic energy


  0.5 x mass x (speed)²
• Elastic potential energy


  0.5 x spring constant x (extension)²
• Gravitational potential energy


  mass x gravitational field strength x height
• Change in thermal energy

  mass x specific heat capacity x temperature change
• Power


  energy transferred / time
• Efficiency


  useful output energy transfer / total input energy transfer
• Efficiency


  useful power output / total power input
• Charge flow


  current x time
• Potential difference


  current x resistance
• Power


  potential difference x current
• Power


  (current)² x resistance
• Energy transferred


  power x time
• Energy transferred


  charge flow x potential difference
• Potential difference across primary coil x current in primary coil

  potential difference across secondary coil x current in secondary coil
• Density


  mass / volume
• Thermal energy for a change of state

  mass x specific latent heat
• Weight


  mass x gravitational field strength
• Work done


  force x distance (along the line of action of the force)
• Force


  spring constant x extension
• Distance travelled


  speed x time
• Acceleration


  (final velocity)² - (initial velocity)² = 2 x acceleration x distance
• Resultant force


  mass x acceleration
• Momentum


  mass x velocity
• Period


  1 / frequency
• Wave speed


  frequency x wavelength
• Force on a conductor (at right angles to a magnetic field) carrying a current


  magnetic flux density * current * length
• Kinetiv energy 


  Ek= ½mv²
• Elastic potential energy 


  Ee=½ke²
• Gravitational potential energy


  Ep= mgh