Force
In physics, a force is any interaction that, when unopposed, will change the motion of an object. A force can cause an object with mass to change its velocity (which includes to begin moving from a state of rest), i.e., to accelerate. Force can also be described intuitively as a push or a pull. A force has both magnitude and direction, making it a vector quantity. It is measured in the SI unit of newtons and represented by the symbol F.
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.