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 were several collieries in Darcy Lever, the Darcy Lever Pit, Davenport Pit, Snow Hill Pit, Victoria Pit, Top o'th'Meadows Colliery. In addition closer to Farnworth there was Fogg Pit owned by Andrew Knowles and Sons, near the Bolton and Bury Canal, which was the scene of an explosion which killed 10 miners. Darcy Lever was a township or civil parish in the ecclesiastical parish of Bolton le Moors in the Salford hundred in the historic county of Lancashire and in 1837 became part of the Bolton Poor Law Union. In 1898 Darcy Lever was incorporated into the County Borough of