Physics equations

• weight

  Mass x gravitational field strength
• kinetic energy

  0.5 x mass x velocity^2
• gravitational potential energy

  weight x height
• Efficiency

  useful output/ useful input
• charge

  current x time
• Voltage definition

  energy transferred/ charge
• Power (resistance)

  Current^2 x resistance
• Power

  Potential difference x current
• Power (definition)

  energy transferred (or work done)/ time
• resistance

  Voltage/current
• density

  mass/volume
• Resultant force

  mass x acceleration
• Acceleration


  change in velocity/time
• distance

  velocity x time
• momentum

  mass x velocity
• pressure: force pushing on a surface / area of surface
• moment of a force: Force x distance (normal to direction of force)
• work done = force x distance (along the line of action of the force)
• wave speed: frequency x wavelength
• Stretching or squashing an object transfers elastic potential energy
• elastic potential : 0.5 x spring constant x extension^2
• force applied to a spring = spring constant x extension