In AC circuits, a "factor" named for this quantity is equal to the cosine of the phase angle. In optics, one form of this quantity is equal to the reciprocal of the focal length. It also equal to sound intensity times area; taking the ratio of two values of it gives the decibel. In fluid dynamics it is equal to the pressure times the flow rate. In 
In AC circuits, a "factor" named for this quantity is equal to the cosine of the phase angle. In optics, one form of this quantity is equal to the reciprocal of the focal length. It also equal to sound intensity times area; taking the ratio of two values of it gives the decibel. In fluid dynamics it is equal to the pressure times the flow rate. In electrical components this is equal to the square of current times resistance or voltage times current, while in mechanics it can be defined as torque times angular velocity or force times velocity. For 10 points, give this term from physics equal to the rate of change of work over time, typically measured in watts.
In AC circuits, a "factor" named for this quantity is equal to the cosine of the phase angle.
{power}