Equations

• Elastic potential energy


  $Ee =$$0.5 k e^2$
• Kinetic energy

  $Ek =$$0.5 m v^2$
• Gravitational potential energy

  $Ep =$$m g h$
• Change in thermal energy

  $ΔE =$$m c Δ θ$
• Power, the rate of doing work

  $P =$$W/t$
• Power, energy transferred

  $P =$$E/t$
• Efficiency for any energy transfer

  Efficiency = useful output energy transfer/total input energy transfer
• Efficiency with power input and output

  Efficiency = useful power output/total power input
• Charge flow


  $Q =$$I t$
• Potential difference 


  $V =$$I R$
• Elastic power


  $P =$$V I$
• Power without Potential difference

  $P =$$I^2 R$
• Power the rate of energy transfer

  $P =$$E/t$
• Energy transferred

  $E =$$Q V$
• Potential difference across primary coil

  $Vp Ip =$$Vs I s$
• Density


  $p =$$m/v$
• Thermal energy for a change of state

  $E =$$m L$