Lever force F at a point "A" located by the coordinate vector r on the bar. The lever then exerts an output force F at the point "B" located by r. The rotation of the lever about the fulcrum "P" is defined by the rotation angle "θ" in radians. Let the coordinate vector of the point "P" that defines the fulcrum be r, and introduce the lengths which are the distances from the fulcrum to the input point "A" and to the output point "B", respectively. Now introduce the unit vectors e and e from the fulcrum to the point "A"
Darcy Lever several ways, whilst the spellings differ the pronunciation was similar to 'lever' – Lethre 1221; Leuere 1278; Leuir 1282; Leuer 1291 and Leyver 1550. Initially, Lever was the name for the hamlets comprising the manor of Lever. In 1509 it became Darcye Lever, the distinguishing affix coming from possession by the D'Arcy family. "NOTE : Until 1509 the area called Darcy Lever today was part of the Manor of Little Lever. In the text, where the name is given in italicised text with square brackets, it refers to the area of Darcy Lever before it gained that name." Darcy Lever