Power

Summary

• Definition
  • Power is the rate at which work is done (or the rate at which energy is transformed or transferred).

    non-calculus	calculus
    P =  ∆W ∆t	P =  dW dt

    Where

    P =	power
    W =	work
    t =	time

  • Power is also the scalar product of force and velocity.

    simplified	non-calculus	calculus
    P = F∥v	P = Fv cos θ	P = F ⋅ v

    Where

    P =	power
    F∥ =	component of force parallel to direction of motion
    F =	magnitude of force
    F =	force vector
    v =	magnitude of velocity
    v =	velocity vector
    θ =	angle between force and velocity

• Units
  • The SI unit of power is the watt, named after the 18th century Scottish engineer James Watt.

    [W = J/s = kg m²/s³]