There are two frequently used systems of units for physical properties. The mks System employs the meter (m) and kilogram (kg) as the units of distance and inertial mass, whereas the British System employs foot (ft) and pound (lb) in their place. In many cases, a conversion between the numerical values of a given object can be obtained by simply making use of the respective ratios of these quantities. It is helpful to realize that any physical property can be expressed as a product of the variables of distance, inertial mass and time. One can expand the applicability of the two Systems to the description of electromagnetic properties by adding the Coulomb (Coul) to this list. The situation is made more complicated by the fact that the British System employs a unit of force (lbf) which depends on the location of the object lying within a gravitational field with a particular value of g. As a consequence, 1 lbf = 4.44822 N = 32.173722 ft lb / s2 within the British System itself. Relationships between the units of energy and power are also disussed.