The poundal is a non-SI unit of force. It is a part of the foot-pound-second system of units, a coherent subsystem of English units introduced in 1879, and one of several specialized subsystems of mechanical units used as aids in calculations. It is defined as 1 lb·ft·s−2, or in words, as the force necessary to accelerate a pound of mass at 1 foot per second, per second.1 pdl = 0.138 254 954 376 N exactly. English units require re-scaling of either force or mass to eliminate a nu… (More on Poundal)