Poundal

The poundal (symbol: pdl) is a unit of force, introduced in 1877, that is part of the Absolute English system of units, which itself is a coherent subsystem of the foot–pound–second system.

${\displaystyle 1\,{\text{pdl}}=1\,{\text{lb}}{\cdot }{\text{ft}}/{\text{s}}^{2}}$

The poundal is defined as the force necessary to accelerate 1 pound-mass at 1 foot per second per second. 1 pdl = 0.138254954376 N exactly.