Pressure measurement
Many other hybrid units are used such as mmHg/cm or grams-force/cm (sometimes as kg/cm without properly identifying the force units). Using the names kilogram, gram, kilogram-force, or gram-force (or their symbols) as a unit of force is prohibited in SI; the unit of force in SI is the newton (N).
Poundal
English units require re-scaling of either force or mass to eliminate a numerical proportionality constant in the equation "F = ma". The poundal represents one choice, which is to rescale units of force. Since a pound of "force" (pound force) accelerates a pound of "mass" (pound mass) at 32.174 049 ft/s (9.80665 m/s; the acceleration of gravity, "g"), we can scale down the unit of force to compensate, giving us one that accelerates 1 pound mass at 1 ft/s rather than at 32.174 049 ft/s; and that is the poundal, which is approximately of a pound force.